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B B Aggarwal

Publications and source records attributed to B B Aggarwal.

At least 91 records · Page 5Linked to original sources
PubMed1998

TR1, a new member of the tumor necrosis factor receptor superfamily, induces fibroblast proliferation and inhibits osteoclastogenesis and bone resorption.

A newly identified member of the tumor necrosis factor receptor (TNFR) superfamily shows activities associated with osteoclastogenesis inhibition and fibroblast proliferation. This new member, called TR1, was identified from a search of an expressed sequence tag database, and encodes 401 amino acids with a 21-residue signal sequence. Unlike other members of TNFR, TR1 does not contain a transmembrane domain and is secreted as a 62 kDa glycoprotein. TR1 gene maps to chromosome 8q23-24.1 and its mRNA is abundantly expressed on primary osteoblasts, osteogenic sarcoma cell lines, and primary fibroblasts. The receptors for TR1 were detected on a monocytic cell line (THP-1) and in human fibroblasts. Scatchard analyses indicated two classes of high and medium-high affinity receptors with a kD of approximately 45 and 320 pM, respectively. Recombinant TR1 induced proliferation of human foreskin fibroblasts and potentiated TNF-induced proliferation in these cells. In a coculture system of osteoblasts and bone marrow cells, recombinant TR1 completely inhibited the differentiation of osteoclast-like multinucleated cell formation in the presence of several bone-resorbing factors. TR1 also strongly inhibited bone-resorbing function on dentine slices by mature osteoclasts and decreased 45Ca release in fetal long-bone organ cultures. Anti-TR1 monoclonal antibody promoted the formation of osteoclasts in mouse marrow culture assays. These results indicate that TR1 has broad biological activities in fibroblast growth and in osteoclast differentiation and its functions.

Animals↗
PubMed1998

Acquisition of cellular resistance to 9-nitro-camptothecin correlates with suppression of transcription factor NF-kappa B activation and potentiation of cytotoxicity by tumor necrosis factor in human histiocytic lymphoma U-937 cells.

Resistance of tumor cells to chemotherapeutic agents is a major problem in cancer therapy. Continuous exposure of human histiocytic lymphoma U-937 cells to 9-nitro-camptothecin (9NC), an inhibitor of the nuclear DNA topoisomerase I, induces resistance to this drug. Because of the involvement of the nuclear factor NF-kappa B in the expression of several growth regulatory genes, we examined the activation of this transcription factor in 9NC-resistant U-937 cells. We found that resistance to increasing concentrations of 9NC correlated with resistance to tumor necrosis factor (TNF)-dependent activation of NF-kappa B. However, the constitutive synthesis of NF-kappa B proteins remained unaffected. Cellular resistance was not unique to TNF, as other activators of NF-kappa B, including interleukin-1, phorbol ester and hydrogen peroxide, also had no effect. There was no difference between 9NC-sensitive and -resistant cells in the activation of NF-kappa B by okadaic acid. Other transcription factors, including AP-1 and Oct-1, were not affected in the resistant cells. When examined for the inhibitory subunit of NF-kappa B (I kappa B alpha), resistant cells showed a faster rate of resynthesis than the control. Interestingly, although 9NC resistance correlated with resistance to TNF-dependent NF-kappa B activation, TNF-dependent cytotoxicity in these cells was enhanced by several hundred fold despite a significant decrease in the number of TNF receptors. In conclusion, our results suggest that NF-kappa B activation may play a role in tumor cell killing by 9NC but not by TNF.

Antineoplastic Agents↗
PubMed1998

Ectopic expression of hepatitis C virus core protein differentially regulates nuclear transcription factors.

The putative core protein of hepatitis C virus (HCV) regulates cellular growth and a number of cellular promoters. To further understand its effect, we investigated the role of the core protein in the endogenous regulation of two distinct transcription factors, nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1), and the related mitogen-activated protein kinase kinase (MAPKK) and c-Jun N-terminal kinase (JNK). Stable cell transfectants expressing the HCV core protein suppressed tumor necrosis factor (TNF)-induced NF-kappaB activation. Supershift analysis revealed that NF-kappaB consists of p50 and p65 subunits. This correlated with inhibition of the degradation of IkappaBalpha, the inhibitory subunit of NF-kappaB. The effect was not specific to TNF, as suppression in core protein-expressing cells was also observed in response to a number of other inflammatory agents known to activate NF-kappaB. In contrast to the effect on NF-kappaB, the HCV core protein constitutively activated AP-1, which correlated with the activation of JNK and MAPKK, which are known to regulate AP-1. These observations indicated that the core protein targets transcription factors known to be involved in the regulation of inflammatory responses and the immune system.

Base Sequence↗
PubMed1998

Serum cytokine levels in infectious mononucleosis at diagnosis and convalescence.

Infection with the Epstein-Barr virus (EBV) is common worldwide. A significant number of infected individuals develop infectious mononucleosis (IM). IM is manifested in most patients as a benign disease with mild symptoms. However, serious complications may develop in a subset of patients. Because EBV-infected B lymphocytes produce various cytokines that may provide the cells with a proliferative advantage, cytokine concentrations in serum samples taken from IM patients were measured in order to identify the cytokines responsible for the clinical manifestations of the disease. The concentrations of interleukin-1beta (IL-1beta), IL-2, IL-6, IL-8, IL-10, tumor necrosis factor-alpha (TNF-alpha), and lymphotoxin (LT) were measured using an enzyme-linked immunosorbent assay (ELISA) in serum obtained from 14 IM patients during the acute phase of the disease and during convalescence, 5 patients with identical clinical manifestations who did not have IM (sick controls), and 11 healthy volunteers. It was found that the serum levels of TNF-alpha and IL-6 were significantly high in patients with acute IM compared with the serum levels in healthy individuals (P = 0.008 and P < 0.001, respectively) but returned to normal at convalescence (P = 0.009 and P = 0.005 respectively). However, whereas TNF-alpha concentrations were significantly higher (P = 0.04) in patients with acute IM than in the sick controls, no significant difference in IL-6 concentrations was found between the two groups of patients. Changes in IL-10 concentration were not statistically significant, and IL-1beta, IL-2, IL-8, and LT were detected only sporadically. The data in this study suggest that TNF-alpha may have a specific role in causing the clinical manifestations of IM. Further studies should determine the clinical significance of TNF-alpha inhibition in IM.

Convalescence↗
PubMed1997

Sanguinarine (pseudochelerythrine) is a potent inhibitor of NF-kappaB activation, IkappaBalpha phosphorylation, and degradation.

The nuclear factor NF-kappaB is a pleiotropic transcription factor whose activation results in inflammation, viral replication, and growth modulation. Due to its role in pathogenesis, NF-kappaB is considered a key target for drug development. In the present report we show that sanguinarine (a benzophenanthridine alkaloid), a known anti-inflammatory agent, is a potent inhibitor of NF-kappaB activation. Treatment of human myeloid ML-1a cells with tumor necrosis factor rapidly activated NF-kappaB, this activation was completely suppressed by sanguinarine in a dose- and time-dependent manner. Sanguinarine did not inhibit the binding of NF-kappaB protein to the DNA but rather inhibited the pathway leading to NF-kappaB activation. The reversal of inhibitory effects of sanguinarine by reducing agents suggests a critical sulfhydryl group is involved in NF-kappaB activation. Sanguinarine blocked the tumor necrosis factor-induced phosphorylation and degradation of IkappaBalpha, an inhibitory subunit of NF-kappaB, and inhibited translocation of p65 subunit to the nucleus. As sanguinarine also inhibited NF-kappaB activation induced by interleukin-1, phorbol ester, and okadaic acid but not that activated by hydrogen peroxide or ceramide, the pathway leading to NF-kappaB activation is likely different for different inducers. Overall, our results demonstrate that sanguinarine is a potent suppressor of NF-kappaB activation and it acts at a step prior to IkappaBalpha phosphorylation.

Alkaloids↗
PubMed1997

Human immunodeficiency virus-1-tat protein induces the cell surface expression of endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in human endothelial cells.

Human vascular endothelial cells (EC) have been implicated in the dissemination of human immunodeficiency virus type-1 (HIV-1). HIV-1-tat, a viral gene product essential for HIV replication, has been shown to interact with different cell types, altering their growth and inducing gene expression. In the present report, we have examined the effect of HIV-tat on the expression of various adhesion molecules in human umbilical vein EC. Our results show that treatment of EC with HIV-tat induces the cell surface expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and endothelial leukocyte adhesion molecule-1 in a time- and dose-dependent manner. Cycloheximide abolished the HIV-tat-dependent induction of all the adhesion molecules, indicating that protein synthesis was required for induction. The effect of HIV-tat on expression of adhesion molecules was potentiated by tumor necrosis factor (TNF), a well-known inducer of adhesion molecules. Like TNF, HIV-tat also enhanced the adhesion of human promyelomonocytic HL-60 cells to EC, and this effect was abolished by treatment with antibodies either against HIV-tat or adhesion molecules. Our results thus indicate that the HIV-tat protein can activate human vascular EC to induce the expression of various adhesion molecules that may play a role in the extravasation of HIV-infected cells.

Cycloheximide↗
PubMed1997

Antitumor activity of the novel human breast cancer growth inhibitor, mammary-derived growth inhibitor-related gene, MRG.

A novel human tumor growth inhibitor was identified by differential cDNA sequencing. The predicted amino acid sequence of this tumor-suppressing factor has a significant sequence homology to mouse mammary-derived growth inhibitor and thus was named mammary-derived growth inhibitor-related gene (MRG). MRG was found to be expressed in normal and benign human breast tissues but not in breast carcinomas. In situ hybridization analysis demonstrated a stage-specific MRG expression as follows. MRG was barely detectable in breast carcinomas, showed partial and weak expression in benign hyperplasia, but was expressed at a high level in normal breast epithelial cells. To determine if MRG can modulate in vivo growth of human breast cancers, we transfected a full-length MRG cDNA into MDA-MB-231 human breast cancer cells and studied the orthotopic growth of MRG transfectants versus control transfectants in the mammary fat pad of athymic nude mice. Overexpression of MRG in human breast cancer cells significantly suppressed cell proliferation in vitro and tumor growth in an orthotopic nude mouse model. These results suggest that MRG has tumor-suppressing activity, and the loss of MRG expression may be involved in the development and progression of breast cancer.

Amino Acid Sequence↗
PubMed1997

Inhibition of protein tyrosine phosphatases causes phosphorylation of tyrosine-331 in the p60 TNF receptor and inactivates the receptor-associated kinase.

Inhibition of protein tyrosine phosphatases blocks tumor necrosis factor (TNF)-induced growth modulation and NF-kappaB activation, both mediated primarily through the p60 TNF receptor. How inhibition of the phosphatases affects the p60 TNF receptor or the recently described receptor-associated serine/threonine kinase (p60TRAK) is not known. In this report, we show that this inhibition, when induced by pervanadate, caused the tyrosine phosphorylation of the cytoplasmic domain (CD) of the p60 receptor, as revealed by phosphoamino acid analysis. Furthermore, site-directed mutagenesis indicated that pervanadate specifically induced the phosphorylation of tyrosine-331, which is located in the death domain of the TNF receptor, a domain to which p60TRAK binds. This tyrosine residue was also phosphorylated by purified, recombinant pp60Src in vitro. Inhibition of protein tyrosine phosphatases by pervanadate also led to the inactivation of p60TRAK. In contrast, okadaic acid, a specific inhibitor of protein serine/threonine phosphatase, increased p60TRAK activity. Taken together, these results suggest that protein tyrosine phosphatases play an essential role in phosphorylation of the cytoplasmic domain of the TNF receptor and in regulation of the receptor-associated kinase, and this in turn may play a role in TNF-mediated growth modulation and NF-kappaB activation.

Amino Acid Sequence↗
PubMed1997

The p80 TNF receptor-associated kinase (p80TRAK) associates with residues 354-397 of the p80 cytoplasmic domain: similarity to casein kinase.

The cytoplasmic domain of the p80 TNF receptor associates with a protein kinase, termed p80TRAK, that phosphorylates both the p60 and p80 TNF receptors. To determine the region of the cytoplasmic domain that is necessary for binding of p80TRAK and the region that it phosphorylates, a series of deletions of the p80 cytoplasmic domain were constructed and expressed as glutathione-S-transferase fusion proteins. These fusions were then used to examine the binding of p80TRAK derived from cellular extracts. We found that out of 174 residues (266-439) in the cytoplasmic domain of p80 receptor, 44 residues (354-397) were sufficient for binding of p80TRAK. Interestingly, this was also the region that contained the phosphorylation site for p80TRAK. Phosphoamino acid analysis of this region revealed phosphorylation primarily on serine residues. Furthermore, we found that, like p80TRAK, purified casein kinase 1 (CK1) also binds to residues 354-397 of the p80 TNF receptor and causes its phosphorylation. Additionally, the activity of p80TRAK was inhibited by CK1-7, the CK1-specific inhibitor. Thus, our results indicate that p80TRAK associates with a short stretch of approximately 44 residues located in the cytoplasmic domain of the p80 TNF receptor and that this kinase is similar to CK1.

Antigens, CD↗
PubMed1997

Activation of CPP32-like protease in tumor necrosis factor-induced apoptosis is dependent on mitochondrial function.

Mitochondria have been implicated in apoptosis, however, the precise mechanisms whereby mitochondria exert their effect are not clear. To gain further insights, we generated a panel of cells from ML-1a cells that were rendered respiration deficient by ethidium bromide treatment. Two respiration-deficient clones were subsequently reconstituted by fusion with platelets. Respiration-deficient clones were resistant to TNF-induced apoptosis, whereas ML-1a and reconstituted clones were sensitive. In contrast, inhibition of proliferation and induction of differentiation by TNF were still observed in respiration deficient clones, suggesting a selective requirement of respiration in TNF-induced apoptosis. Furthermore the apoptosis machinery is not completely altered in respiration-deficient cells because they underwent apoptosis after staurosporine treatment. Next, we showed that apoptosis induced by TNF and staurosporine were blocked by z-DEVD-CH2F, an inhibitor of CPP32-like cysteine protease, suggesting the involvement of CPP32-like protease in both apoptosis signaling pathways. Interestingly, TNF activated CPP32-like protease in the parental and reconstituted clones but not in respiration-deficient clones, and staurosporine in all clones. Thus, the apoptosis signaling block in respiration-deficient clones is located at a step before CPP32-like protease activation, which can be bypassed by staurosporine.

Apoptosis↗
PubMed1997

Induction of endothelial cell surface adhesion molecules by tumor necrosis factor is blocked by protein tyrosine phosphatase inhibitors: role of the nuclear transcription factor NF-kappa B.

Recent studies from our laboratory have indicated that protein tyrosine phosphatase (PTPase) inhibitors can down-modulate the tumor necrosis factor (TNF)-mediated activation of the nuclear transcription factor NF-kappa B in ML-1a, a monocytic cell line (Singh and Aggarwal, J. Biol. Chem. 1995: 270: 10631). Since TNF is one of the major inducers of various adhesion molecules in human endothelial cells and their expression is known to require the activation of NF-kappa B, we examined the effect of PTPase inhibitors on the TNF-mediated induction of intracellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1 and endothelial leukocyte adhesion molecule (ELAM)-1. Like ML-1a, human dermal microvessel endothelial cells (MVEC) treated with TNF rapidly activated (within 30 min) NF-kappa B; this effect was completely abolished by co-treatment with phenylarsine oxide (PAO), a specific inhibitor of PTPase. The induction of ICAM-1, VCAM-1, and ELAM-1 by TNF in MVEC occurred within 6 h and was also completely down-regulated by PAO in a dose-dependent manner. PAO was found to be effective even when added 3 h after TNF, suggesting a rapid mode of action of this inhibitor. Besides PAO, other inhibitors of PTPase, including pervanadate and diamide, also blocked TNF-dependent NF-kappa B activation and induction of all the three adhesion proteins. Consistent with these results, the attachment of monocytes to MVEC was also blocked by the PTPase inhibitors. Thus, overall, our results demonstrate that a PTPase is involved either directly or indirectly in the pathway leading to the induction of endothelial cell adhesion molecules by TNF. Because of their role in cell adhesion, PTPase may provide a novel target of drug development for treatment of inflammation, atherogenesis, and tumor metastasis.

Arsenicals↗
PubMed1997

Early events in TNF signaling: a story of associations and dissociations.

At the cellular level, the multifunctional cytokine tumor necrosis factor (TNF) modulates growth and activates genes through various intermediates, including protein kinases, protein phosphatases, reactive oxygen intermediates, phospholipases, proteases, sphingomyelinases, and transcription factors. Unlike many cytokine receptors, however, the cytoplasmic domain (CD) of the TNF receptors lacks an intrinsic protein kinase activity and yet on interaction with ligand it phosphorylates various proteins. Although the kinetics of most of these activities differ, their interactions are coordinated through the selective interplay between the CD of the receptors and the associated proteins. A unique pathway has been identified by the ability of the TNF receptors to associate with a novel family of proteins. Two distinct families of proteins have emerged, the TNF receptor-associated factors (TRAFs) and the death domain homologues. The cloning of members of these gene families and the identification of the protein-interaction motifs found within their gene products has initiated the molecular identity of factors (TRADD, FADD/MORT, RIP, FLICE/MACH, and TRAFs) associated with both of the p60 and p80 forms of the TNF receptor and with other members of the TNF receptor superfamily. In this review, we summarize these and other TNF receptor-associated proteins and their potential roles in regulating the activation of nuclear factor-kappaB and apoptosis, two major responses activated by engagement of TNF receptors by the ligand.

Animals↗
PubMed1997

Epstein-Barr Virus EBNA-2 gene expression enhances lymphotoxin production by B lymphocytes.

Epstein-Barr Virus (EBV) effectively transforms B lymphocytes into long-term cell lines or tumors through the interaction of viral gene products and cellular proteins induced secondary to the virus infection. The latent membrane protein (LMP) gene, the EBV nuclear antigens (EBNAs) 1 and 2, and the origin of replication genes of the virus are the principal viral effectors of transformation. One of the cellular proteins that enhances the growth and proliferation of B cells is lymphotoxin (LT). We have found that Burkitt's lymphoma cells containing a strain of EBV with a deletion in EBNA-2 had lower constitutive and inducible levels of LT compared to LT production in Burkitt's cells with competent EBV or lymphoblastoid cell lines actively producing EBV. Also, the LT production in the latter cell lines was greater than in cells in which the infecting EBV had a deletion in the LMP gene. The relative decrease in LT production associated with deletions in the LMP was less than that found with EBNA-2 deletions. Overall our results indicate that the EBNA-2 gene enhances the capacity of EBV-infected cells to produce LT.

B-Lymphocytes↗
PubMed1997

Antiproliferative effect of curcumin (diferuloylmethane) against human breast tumor cell lines.

Pharmacologically safe compounds that can inhibit the proliferation of tumor cells have potential as anticancer agents. Curcumin, a diferuloylmethane, is a major active component of the food flavor turmeric (Curcuma longa) that exhibits anticarcinogenic properties in vivo. In vitro, it suppressed c-jun/Ap-1 and NF-kappaB activation and type 1 human immunodeficiency virus long-terminal repeat-directed gene expression. We examined the antiproliferative effects of curcumin against several breast tumor cell lines, including hormone-dependent and -independent and multidrug-resistant (MDR) lines. Cell growth inhibition was monitored by [3H]thymidine incorporation, Trypan blue exclusion, crystal violet dye uptake and flow cytometry. All the cell lines tested, including the MDR-positive ones, were highly sensitive to curcumin. The growth inhibitory effect of curcumin was time- and dose-dependent, and correlated with its inhibition of ornithine decarboxylase activity. Curcumin preferentially arrested cells in the G2/S phase of the cell cycle. Curcumin-induced cell death was neither due to apoptosis nor to any significant change in the expression of apoptosis-related genes, including Bcl-2, p53, cyclin B and transglutaminase. Overall our results suggest that curcumin is a potent antiproliferative agent for breast tumor cells and may have potential as an anticancer agent.

Antibiotics, Antineoplastic↗
PubMed1996

Site-specific tyrosine phosphorylation of IkappaBalpha negatively regulates its inducible phosphorylation and degradation.

The transcription factor NF-kappaB is retained in the cytoplasm by its interaction with the inhibitory subunit known as IkappaB. Signal-induced serine phosphorylation and subsequent ubiquitination of IkappaBalpha target it for degradation by the 26 S proteasome. Recently, pervanadate, a protein-tyrosine phosphatase inhibitor, was shown to block the degradation of IkappaBalpha, thus inhibiting NF-kappaB activation. We investigated the mechanism by which pervanadate inhibits the degradation of IkappaBalpha. Western blot analysis of IkappaBalpha from tumor necrosis factor-treated cells revealed a slower migrating IkappaBalpha species that was subsequently degraded. However, pervanadate-treated cells also revealed a slower migrating species of IkappaBalpha that appeared in a time- and dose-dependent manner and was not degraded by tumor necrosis factor. The slower migrating species of IkappaBalpha from pervanadate-treated cells was tyrosine-phosphorylated as revealed by cross-reactivity with anti-phosphotyrosine antibodies, by the ability of the specific tyrosine phosphatase PTP1B to dephosphorylate it, and by phosphoamino acid analysis of IkappaBalpha immunoprecipitated from 32P-labeled cells. By site-specific mutagenesis and deletion analysis, we identified Tyr-42 on IkappaBalpha as the phosphoacceptor site. Furthermore, in an in vitro reconstitution system, tyrosine-phosphorylated IkappaBalpha was protected from degradation. Our results demonstrate that inducible phosphorylation and degradation of IkappaBalpha are negatively regulated by phosphorylation at Tyr-42, thus preventing NF-kappaB activation.

Amino Acid Sequence↗
PubMed1996

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is a potent inhibitor of nuclear transcription factor-kappa B activation by diverse agents.

Viral replication, immune regulation, and induction of various inflammatory and growth-regulatory genes require activation of a nuclear transcription factor (NF)-kappa B. Agents that can block NF-kappa B activation have potential to block downstream responses mediated through this transcription factor. Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is a quinone that has been shown to regulate a wide variety of activities that require NF-kappa B activation. In the present study, we examined the effect of capsaicin and its analogue, resiniferatoxin, on the activation of NF-kappa B induced by different agents including TNF. The pretreatment of human myeloid ML-1a cells with capsaicin blocked TNF-mediated activation of NF-kappa B in a dose- and time-dependent manner. Resiniferatoxin was at least eight times as potent as capsaicin in inhibiting NF-kappa B activation. Neither agent by itself activated NF-kappa B or affected the DNA-binding ability of NF-kappa B. Capsaicin also blocked phorbol ester-mediated NF-kappa B activation, but that mediated through okadaic acid was less effective, suggesting there is a difference in the mechanism of activation of NF-kappa B by different agents. Capsaicin treatment of cells also blocked the degradation of I kappa B alpha, and thus the nuclear translocation of the p65 subunit of NF-kappa B, which is essential for NF-kappa B activation. TNF-dependent promoter activity of I kappa B alpha, which contains NF-kappa B binding sites, was also inhibited by capsaicin. Overall our results indicate that capsaicin and its analogue inhibit NF-kappa B activation, and thus could be used as a potential target for drug development.

Capsaicin↗
PubMed1996

Triple helix-forming oligodeoxyribonucleotides targeted to the human tumor necrosis factor (TNF) gene inhibit TNF production and block the TNF-dependent growth of human glioblastoma tumor cells.

Synthetic oligodeoxyribonucleotides (ODNs) designed to selectively inhibit the transcription or translation of specific genes are being used to modulate the activity of the targeted gene. Because multiple copies of mRNA can be transcribed from one actively expressed gene, ODNs that target double-stranded DNA and form triple helices upon binding with the gene itself have an advantage over ODNs that target the gene product (mRNA) in an antisense fashion. For the present studies, we designed four different triple helix-forming phosphodiester ODNs (TFOs) targeted to the tumor necrosis factor (TNF) gene and examined their effect on production of TNF and on cellular growth of tumors in which TNF acts as an autocrine growth factor. The ODNs J-109-50 and J-108-57 were designed to interact with polypurine oligonucleotides corresponding to the binding sites for nuclear factors kB (-237 to -208) and Sp1 (-58 to -33), respectively; J111-51 was designed to interact with a polypurine oligonucleotide in the third intron (+1429 to +1456) of the TNF gene. To enhance the cellular penetration and prevent degradation by cellular nucleases, the TFOs were modified at their 3' ends by either a cholesterol side chain or a propanolamine blocking group. Treatment of the human promonocytic cell line THP-1 with TNF-TFOs at a nontoxic concentration (2 microM) reduced the production of TNF. All of the TNF-TFOs tested were effective, and control-irrelevant TFOs were ineffective in inhibiting TNF production. The activity of the most efficacious TNF-TFOs also correlated with a decrease in TNF mRNA as observed by using reverse transcriptase PCR assays. In several tumors in which TNF acts as an autocrine growth factor, we examined the antiproliferative activity of J111-51. We found that in the human glioblastoma tumor cell line U-251, TNF-induced growth was blocked by J111-51 in a dose-dependent manner. Thus, overall results demonstrate that oligonucleotides directed to the specific regions of TNF can be designed, which may have a potential in cancer therapy.

Animals↗