Potent Synergistic Activity Research Articles

Oral poly(ADP-ribose) polymerase-1 inhibitor BSI-401 has antitumor activity and synergizes with oxaliplatin against pancreatic cancer, preventing acute neurotoxicity.

Development of novel agents and drug combinations are urgently needed for treatment of pancreatic cancer. Oxaliplatin belongs to an important class of DNA-damaging organoplatinum agents, useful in pancreatic cancer therapy. However, increased ability of cancer cells to recognize and repair DNA damage enables resistance to these agents. Poly (ADP ribose) polymerase-1 is a sensor of DNA damage with key roles in DNA repair. Here, we report the therapeutic activity of the poly (ADP ribose) polymerase-1 inhibitor BSI-401, as a single agent and in combination with oxaliplatin in orthotopic nude mouse models of pancreatic cancer, and its effect on oxaliplatin-induced acute neurotoxicity. We determined in vitro the effect of BSI-401 and its synergism with oxaliplatin on the growth of pancreatic cancer cells. Activity of different dosages of parenteral and oral BSI-401, alone and in combination with oxaliplatin, was evaluated in orthotopic nude mouse models with luciferase-expressing pancreatic cancer cells. The effect of BSI-401 in preventing oxaliplatin-induced acute cold allodynia was measured in rats using a temperature-controlled plate. BSI-401 alone and in synergism with oxaliplatin significantly inhibited the growth of pancreatic cancer cells in vitro. In nude mice, i.p. [200 mg/kg once a week (QW) x 4] and oral [400 mg/kg days 1-5 of each week (QD5 + R2) x 4] administration of BSI-401 significantly reduced tumor burden and prolonged survival (46 versus 144 days, P = 0.0018; 73 versus 194 days, P = 0.0017) compared with no treatment. BSI-401 combined with oxaliplatin had potent synergistic antitumor activity (46 versus 132 days, P = 0.0063), and significantly (P = 0.0148) prevented acute oxaliplatin-induced neurotoxicity. BSI-401, alone or in combination with oxaliplatin, is a promising new therapeutic agent that warrants further evaluation for treatment of pancreatic cancer.

Antibacterial Activity and Synergism of the Hybrid Antimicrobial Peptide, CAMA-syn

A 20-residue hybrid peptide CA(1-8)-MA(1-12) (CAMA) incorporating residues 1-8 of cecropin A (CA) and residues 1-12 of magainin 2 (MA) has high antimicrobial activity without toxicity. To investigate the effects of the total positive charges of CAMA on the antibacterial activity and toxicity, a hybrid peptide analogue (CAMA-syn) was designed with substitutions of <TEX>$Ile^{10}\;and\;Ser^{16}$</TEX> with Lys. According to CD spectra, structure of CAMA-syn with increase of cationicity was very similar to that of CAMA in DPC micelle. CAMA-syn showed antimicrobial activity similar with CAMA while CAMA-syn has no hemolytic activity and much lower cytotoxicity against RAW 264.7 macrophage cells than CAMA. Also, CAMA and CAMA-syn significantly inhibited NO production by LPSstimulated RAW264.7 macrophage at 10.0∼20.0 <TEX>$\mu$</TEX>M. CAMA-syn displayed salt resistance on antimicrobial activity against Escherichia coli at the physiological concentrations of <TEX>$CaCl_2\;and\;MgCl_2$</TEX>. The combination studies of peptides and antibiotics showed that CAMA-syn has synergistic effects with synthetic compound and flavonoid against Enterococcus faecalis and VREF. CAMA-syn can be a good candidate for the development of new antibiotics with potent antibacterial and synergistic activity but without cytotoxicity.

A novel selective therapeutic targeting heme oxygenase-1 revealed a potent antimetastatic activity in androgen-refractory human prostate cancer models

e16090 Prostate cancer is a highly prevalent disease. Despite a significant improvement in the overall survival attributed in part to early detection and introduction of novel therapeutic modalities, many cancer patients at primary diagnosis present advanced disease or experience recurrence of the cancer. The progression of prostate cancer (PCA) to hormone-refractory phenotype (HRPCA) and to metastasis is an ominous event in patients with advanced PCA. Currently, clinically available drugs for hormone refractory PCA have only marginal efficacy. In this study, we identified heme oxygenase 1 (HO-1) to be significantly upregulated in epithelial PCA cells, but not in surrounding stromal cells, from hormone refractory prostate cancer cases compared to hormone-responsive prostate cancer and to benign tissues. We validated HO-1 as a novel therapeutic target for HRPCA. Specifically, inhibition of HO-1 gene in androgen-independent and highly invasive prostate cancer cells, PC3M, decreased HO-1 activity, oxidative stress, MAPKs activation, cell proliferation, and cell migration and invasion in vitro, as well as inhibition of prostate tumor growth and lymph nodes and lung metastases in vivo. The impact of HO-1 silencing on these oncogenic features was mimicked by exposure of cells to a novel selective small-molecule HO-1 inhibitor referred to as OB-24. OB-24 selectively downregulates HO-1 activity, oxidative stress, and significantly inhibits cell proliferation in vitro and tumor growth and lymph node/lung metastases in vivo. A potent synergistic activity in inhibiting HRPCA metastasis formation was observed when OB-24 was combined with the chemotherapy drug taxol. The molecular and potential clinical impact of OB-24 alone and in combination with taxanes on HRPCA will be discussed. [Table: see text]

Abstract 1718: Combination of Direct Acting FXa Inhibitor and P2Y 12 Antagonist at Non-Effective doses Provides Significant Inhibition of Arterial Thrombosis

Previous studies have shown that inhibition of FXa and P2Y 12 used individually inhibit arterial thrombosis. The present study was designed to determine the antithrombotic activity achieved by the combination of non-effective doses of PRT054021 (FXa inhibitor) and PRT060128 (P2Y 12 antagonist). Arterial thrombosis was achieved by FeCl 3 injury of mesenteric arteries of the mouse and monitored in real time using intravital microscopy. Antagonism of either FXa or P2Y 12 dose-dependently inhibited early (time for appearance of first thrombus, TFFT) and late (time to vascular occlusion, TTO) phases of thrombosis (see Table ). Maximal effects were achieved at plasma concentrations superior or equal to 1 μg/ml for the two antagonists. Interestingly, the co-administration of non-effective doses of PRT054021 and PRT060128 significantly delayed time for appearance of first thrombus and vascular occlusion, demonstrating potent synergistic antithrombotic activity. PRT054021 and PRT060128 demonstrated a strong synergistic effect when administered in combination at non-effective doses. This combination is of particular relevance in acute settings, when thrombotic risk is at its paroxysm and maximal protection is sought as early as possible. These data also indicate that combined inhibition of FXa and P2Y 12 by reversible antagonists could provide substantial benefits to ACS patients throughout the chronic phase of the disease.

In Vitro and In Vivo Antitumorigenic Activity of a Mixture of Lysine, Proline, Ascorbic Acid, and Green Tea Extract on Human Breast Cancer Lines MDA-MB-231 and MCF-7

Current treatments are generally ineffective once breast cancer has metastasized; median survival is reduced to 2-3 yr. Previous research studies demonstrating potent synergistic antitumor activity of lysine, proline, ascorbic acid, and epigallocatechin gallate prompted us to investigate the in vivo inhibitory effect of a nutrient mixture containing lysine, proline, arginine, ascorbic acid, and epigallocatechin gallate (NM) on the growth of human cancer xenografts in female athymic nude mice. Five to six week old female mice were inoculated with 3x106 breast cancer cells MDA-MB-231. After injection, the mice were randomly divided into two groups A and B; group A was fed a regular diet and group B with the regular diet supplemented with 0.5% of the nutrient mixture (NM). Four weeks later, the mice were sacrificed, and their tumors were excised, weighed, and processed for histology. We also tested the effect of NM in vitro on estrogen-receptor positive (ER+) MCF-7 and estrogen-receptor negative (ER-) MDA-MB-231 breast cancer cell lines by measuring: cell proliferation by MTT assay, expression of MMPs by gelatinase zymography, invasion through Matrigel, and VEGF by ELISA. MCF-7 cells were also treated with estradiol to study enhanced invasion and expression of MMPs and VEGF. Results showed that NM inhibited the growth and reduced the size of tumors in female nude mice by 27%. Furthermore, histological evaluation revealed increased mitotic index, MMP-9 and VEGF secretion, and PAS material (mucin) in the control group tissues. In vitro studies showed NM inhibited MDA-MB-231 cell growth by 34% at 500 microg/mL and MCF-7 cell growth by 18% at 1000 microg/mL. Invasion of MDA-MB-231 through Matrigel was inhibited by 50%, 60%, and 95% by 10, 50, and 100 microg/mL of NM, respectively. The results of this study demonstrated that the nutrient mixture tested significantly suppressed tumor growth of breast cancer cells in female athymic nude mice and significantly inhibited MMP expression, angiogenesis, and invasion in breast cancer cells, in vitro, offering promise for therapeutic use in the treatment of breast cancer.

Resveratrol glucuronides as the metabolites of resveratrol in humans: Characterization, synthesis, and anti-HIV activity

Resveratrol is a natural product with diverse biological activities. We have previously reported that resveratrol possesses potent synergistic inhibitory activity against human immunodeficiency virus (HIV)-1 infection in combination with nucleoside analogs (Heredia et al. 2000. J Acquir Immune Defic Syndr 25:246−255). As a part of our program in developing resveratrol as a component for anti-HIV chemotherapy, we describe in this article the characterization, chemical synthesis, and biological effects of the human metabolites of resveratrol. We found that resveratrol was metabolized in humans into two metabolites, which were characterized as resveratrol-3-O- and 4′-O-glucuronides. For further biological studies, we reported two simple, alternative methods for the synthesis of the metabolites. The cytotoxic and antiviral activities of resveratrol and its metabolites were compared in cell culture experiments using human peripheral blood mononuclear cells. Whereas resveratrol was cytotoxic at ≥30μM, no cytotoxicity was observed for the metabolites at concentrations as high as 300μM. However, resveratrol showed strong synergistic anti-HIV activity with didanosine at 10μM, but no synergistic effects were observed for either of the metabolites at up to 300μM. Nevertheless, the in vitro activity of the metabolites (resveratrol glucuronides) may not necessarily reflect their in vivo function, given the fact that the ubiquitously existing human β-glucuronidase could convert the metabolites back to resveratrol locally or systematically in vivo. The present studies have implications for future development of resveratrol and/or its derivatives as a chemotherapeutic agent. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2448−2457, 2004

Retinoidal Pyrimidinecarboxylic Acids. Unexpected Diaza-Substituent Effects in Retinobenzoic Acids.

Several pyridine- and pyrimidine-carboxylic acids were synthesized as ligand candidates for retinoid nuclear receptors, retinoic acid receptors (RARs) and retinoic X receptors (RXRs). Although the pyridine derivatives, 6-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carbamoyl]pyri dine-3-carboxylic acid (2b) and 6-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]py ridine-3-carboxylic acid (5b) are more potent than the corresponding benzoic acid-type retinoids, Am80 (2a) and Am580 (5a), the replacement of the benzene ring of Am580 (5a), Am555 (6a), or Am55 (7a) with a pyrimidine ring caused loss of the retinoidal activity both in HL-60 cell differentiation assay and in RAR transactivation assay using COS-1 cells. On the other hand, pyrimidine analogs (PA series, 10 and 11) of potent RXR agonists (retinoid synergists) with a diphenylamine skeleton (DA series, 8 and 9) exhibited potent retinoid synergistic activity in HL-60 cell differentiation assay and activated RXRs. Among the synthesized compounds, 2-[N-n-propyl-N-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)a mino]pyrimidine-5-carboxylic acid (PA013, 10e) is most active retinoid synergist in HL-60 assay.

The synthesis and evaluation of 6-alkylidene-2'β-substituted penam sulfones as β-lactamase inhibitors

The first 6-alkylidene-2′ β-substituted penams were prepared and selected derivatives shown to be excellent inhibitors of three isolated serine β-lactamases. Some of these also display potent synergistic activity (in combination with piperacillin) against several intact penicillin resistant microorganisms, including Pseudomonas aeruginosa.

Bone morphogenetic protein 9 is a potent synergistic factor for murine hemopoietic progenitor cell generation and colony formation in serum-free cultures.

The effect of the recently cloned cytokine bone morphogenetic protein 9 (BMP-9) on colony formation and generation in vitro clonable hematopoietic progenitors (CFU-C) in serum-free liquid cultures (LC) of both normal and post-5-fluorouracil murine bone marrow cells was studied in the presence of various other cytokines. In LC, BMP-9 concentrations of 100 ng or more per ml led to complete inhibition of Steel Factor (SF) + interleukin-11 (IL-11) or IL-12 supported CFU-C generation, which was partly abrogated when IL-3 was additionally included. We found this inhibitory effect of BMP-9 to be mediated by an increased TGF-beta1 elaboration and TGF-beta1 mRNA expression in bone marrow cells with increasing BMP-9 concentrations. In the presence of neutralizing antibodies (Ab) against TGF-beta1, BMP-9 concentrations of 3 ng or higher synergized with IL-3, SF+IL-3, SF+IL-11/12, or IL-3+SF+IL-11/12 to increase CFU-C generation. Similarly, high BMP-9 concentrations dramatically inhibited primary colony formation induced by SF+IL-11/12, whereas in the presence of TGF-beta1 neutralizing Ab only 3 ng or more BMP-9 per ml stimulated both the time of colony appearance, the colony size and colony numbers in the presence of IL-3, M-CSF, GM-CSF, SF, SF+Flt3-L, SF+IL-3, SF+IL-11/12 or IL-3+SF+IL-11/12. BMP-9 neither stimulated CFU-C generation nor colony formation as a single factor, nor did it synergize with thrombopoietin (Tpo), erythropoietin (Epo), Flt3-L, IL-11, IL-12 or G-CSF. The effect of BMP-9 on its target cells was direct as demonstrated using single-sorted stem cells. These observations demonstrate that BMP-9 plays a dual role in regulating proliferation of primitive hemopoietic progenitor cells. Thus, in addition to its ability to enhance TGF-beta1 elaboration in bone marrow cells, it acts as a potent synergistic activity that is different from SF, Flt3-L, IL-11 or IL-12. BMP-9 mRNA was exclusively detected in the liver of adult mice, whilst no expression was found in stromal cell lines propagated from day-16 fetal liver or neonatal or adult bone marrow. 125I-BMP-9 bound specifically to a high percentage of blast cells in lineage-depleted post-fluorouracil bone marrow cells and to megakaryocytes in normal and post-fluorouracil bone marrow, indicating that BMP-9R are expressed on these cells. The dissociation between the site of BMP-9 production and its target cells in the bone marrow makes BMP-9 a hemopoietic hormone.

Recent progress in anti-influenza chemotherapy.

Influenza virus infections in high risk individuals, such as infants, the elderly, and patients with cardiopulmonary disorders or immunocompromised states, cause severe manifestations which often result in fatalities. The emergence of a new antigen type of influenza A virus (H5N1) in Hong Kong during 1997 and 1998 threatened a possible pandemic of a new influenza infection.The investigation for anti-influenza chemotherapies has progressed in the last decade whereas clinical trials of new compounds have been limited to amantadine, rimantadine and ribavirin. Fusion inhibitors which directly inhibit conformational change of haemagglutinin (HA), protease inhibitors which inhibit cleavage of HA to HA1 and HA2, RNA transcription inhibitors which inhibit cap formation of mRNA and antisense oligonucleotides targeted at mRNA of PB2 (a part of viral RNA polymerase) have been reported, in their development phases.Recently, 2 neuraminidase (NA) inhibitors, zanamivir and oseltamivir (GS 4104), were used in clinical trials for the treatment of patients with influenza. Both agents showed promising results. A polyoxometalate, PM-523, inhibits fusion between the virus envelope and cell membrane and inhibits the penetration of the virus into cells. This compound has shown potent anti-influenza activity and synergistic inhibitory activity in combination with ribavirin or zanamivir in vitro and in vivo.Resistant strains for zanamivir, oseltamivir or PM-523 have been isolated. The analysis of mutation points of these strains have contributed to the investigation of the antiviral mechanisms of action of these compounds and the mechanism of resistance of the mutants to these compounds.

Identification, purification, and biological characterization of hematopoietic stem cell factor from buffalo rat liver-conditioned medium

We have Identified a novel growth factor, stem cell factor (SCF), for primitive hematopoietic progenitors based on its activity on bone marrow cells derived from mice treated with 5-fluorouracil. The protein was isolated from the medium conditioned by Buffalo rat liver cells. It is heavily glycosylated, with both N-linked and O-linked carbohydrate. Amino acid sequence following removal of N-terminal pyroglutamate is presented. The protein has potent synergistic activities in semisolid bone marrow cultures in conjunction with colony-stimulating factors. It is also a growth factor for mast cells. In two companion papers, we present the sequences of partial SCF cDNAs, identify SCF as a c- kit ligand, and map the SCF gene to the SI locus of the mouse.

Primary structure and functional expression of rat and human stem cell factor DNAs

Partial cDNA and genomic clones of rat stem cell factor (SCF) have been isolated. Using probes based on the rat sequence, partial and full-length cDNA and genomic clones of human SCF have been isolated. Based on the primary structure of the 164 amino acid protein purified from BRL-3A cells, truncated forms of the rat and human proteins have been expressed in E. coli and mammalian cells and have been shown to possess biological activity. SCF is able to augment the proliferation of both myeloid and lymphoid hematopoietic progenitors in bone marrow cultures. SCF exhibits potent synergistic activities in conjunction with colony-stimulating factors, resulting in increased colony numbers and colony size.

ChemInform Abstract: SYNTHESIS AND BIOLOGICAL ACTIVITIES OF THE (Z) ISOMERS OF CARBAPENEM ANTIBIOTICS

AbstractIn Gegenwart von quaternären Ammoniumbromiden und ‐chloriden wandelt sich (I) in ein Gemisch aus (I) und (II) mit (II) als Hauptkomponente um.

Synthesis and biological activities of the Z isomers of carbapenem antibiotics.

Naturally occurring carbapenem antibiotics having a double bond in the side chain, when refluxed in chloroform containing quarternary alkylammonium halides, were converted into Z isomers in high yields. The mechanism of this new equilibration involves intramolecular proton transfer from the carboxylic acid to the carbon alpha to the sulfur atom in the side chain as shown by deuterium-labeling experiments. Some Z isomers showed stronger protective effects in mice infected by Escherichia coli O-111 and more potent synergistic activities with cefotiam in mice infected by Proteus vulgaris GN4815 than did the naturally occurring E isomers. The decomposition rates of the Z isomers in mouse kidney homogenates were about 3-fold slower than those of the E isomers.

Joint Insecticidal Effect of &lt;i&gt;N&lt;/i&gt;-Propyl and &lt;i&gt;N&lt;/i&gt;-Methylcarbamates on the Green Rice Leafhopper, Resistant to &lt;i&gt;N&lt;/i&gt;-Methylcarbamates

The green rice leafhoppers, Nephotettix cincticeps Uhler, have developed cross-resistance to many N-methylcarbamate insecticides due to the reduced sensitivity of its acetylcholinesterase (AChE) to the carbamates.We tried to develope new carbamates which could control such resistant leafhopper, and made various structural modifications which would increase the interaction with such altered AChE. Aryl N-propylcarbamates were found to be potent inhibitors of the resistant AChE, but not potent insecticides.Combination of the N-propylcarbamate with N-methylcarbamate with same or different phenyl group gave a potent synergistic insecticidal activity, and were shown to be promising insecticides for practical application.The mechanism was elusidated on biochemical basis. The AChE from resistant leafhopper has the additional site which is sensitive to N-propyl but insensitive to N-methylcarbamates other than the N-methylcarbamate-sensitive site present in AChE from susceptible leafhopper. Single inhibitor could not inhibit both sites, but combining two inhibitors, each interacts with the preferred site. Recognition of such mechanism would provide the chance for finding another chemicals and a rational basis for the use of combined anti-AChEs.