Anti-tumor effect of ultrasound-induced Nordy-loaded microbubbles destruction.

BACKGROUND: Synthesized dl-Nordihydroguaiaretic acid (dl-NGDA or "Nordy") can inhibit the growth of malignant human tumors, especially the tumor angiogenesis. However, its liposoluble nature limits its in vivo efficacy in the hydrosoluble circulation of human. PURPOSE: We tried to use the ultrasonic microbubble as the carrier and the ultrasound-induced destruction for the targeted release of Nordy and evaluate its in vitro and in vivo anti-tumor effect. METHODS: Nordy-loaded lipid microbubbles were prepared by mechanical vibration. Effects of ultrasound-induced Nordy-loaded microbubbles destruction on proliferation of human umbilical vein endothelial cells (HUVECs), tumor derived endothelial cells (Td-ECs), and rabbit transplanted VX2 tumor models were evaluated. RESULTS: The ultrasound-induced Nordy-loaded microbubbles destruction inhibited the proliferations of HUVECs and Td-ECs in vitro, and inhibited the tumor growth and the microvasculature in vivo. Its efficacy was higher than those of Nordy used only and Nordy with ultrasound exposure. CONCLUSION: Ultrasonic microbubbles can be used as the carrier of Nordy and achieve its targeted release with improved anti-tumor efficacy in the condition of ultrasound-induced microbubbles destruction.

Nordihydroguaiaretic acid ameliorates cisplatin induced nephrotoxicity and potentiates its anti-tumor activity in DMBA induced breast cancer in female Sprague-Dawley rats.

Cisplatin is a widely used antineoplastic drug, but its clinical usefulness is limited due to dose dependent nephrotoxicity. Nordihydroguaiaretic acid (NDGA) is a natural compound with broad pharmacological properties like antioxidant, anti-inflammatory and anticancer activity. The present study was undertaken to evaluate the possible beneficial effects of NDGA on cisplatin induced nephrotoxicity as well as its anticancer activity in rats bearing DMBA induced mammary tumors. The effect of NDGA on cisplatin induced nephrotoxicity was evaluated by checking serum nephrotoxicity markers, antioxidant enzymes and inflammatory markers level and kidney histopathology. NDGA induced amelioration of cisplatin nephrotoxicity was clearly visible from significant reductions in serum blood urea nitrogen (86.51 g/dl) and creatinine (5.30 g/dl) levels and significant improvement in body weight change (-10.34 g) and kidney weight (728 mg/kg). The protective effect of NDGA against cisplatin induced nephrotoxicity in the rats was further confirmed by significant restoration of antioxidant enzymes like SOD (86.28% inhibition), inflammatory markers like TNF-α (34.6 pg/ml) and histopathological examination. Moreover, our results showed that NDGA potentiated anti-breast cancer activity of cisplatin through an increment in the expression of antioxidant enzymes like SOD (85.35% inhibition) in breast cancer tissue. These results indicated that NDGA potentiated the anti-breast cancer activity of cisplatin, which was clearly evident from the tumor volume and % tumor inhibition in breast cancer rats. The current study demonstrated that NDGA may modify the therapeutic effect of cisplatin in DMBA induced breast cancer in female Sprague-Dawley rats.

Combination of amniotic epithelial cells with NDGA promotes the survival of transplanted AECs in spinal cord-injured rats.

Our previous research has shown that seeding amniotic epithelial cells (AECs) in chemically extracted acellular muscle scaffold (CEAMC) better promotes the functional recovery of spinal cord injury (SCI) than scaffold alone. However, the massive death of transplanted cells, which is related to early inflammatory response, is still a problem in cell therapy. Our previous study proved that nordihydroguaiaretic acid (NDGA) inhibits inflammation after SCI. In this study, we tested a strategy of combining the early administration of NDGA and the transplantation of AEC-seeded CEAMC to treat SCI. The results showed that simply increasing the number of surviving AECs had no significant benefits in SCI therapy, but NDGA administration ameliorated transplanted AEC survival demonstrating the potential value of NDGA in the cellular transplantation treatment of SCI.

Nordihydroguaiaretic Acid Disrupts the Antioxidant Ability of Helicobacter pylori through the Repression of SodB Activity In Vitro.

Iron-cofactored superoxide dismutase (SodB) of Helicobacter pylori plays an indispensable role in the bacterium's colonization of the stomach. Previously, we demonstrated that FecA1, a Fe(3+)-dicitrate transporter homolog, contributes to SodB activation by supplying ferrous iron (Fe(2+)) to SodB, and fecA1-deletion mutant strains have reduced gastric mucosal-colonization ability in Mongolian gerbils, suggesting that FecA1 is a possible target for the development of a novel eradication therapy. This study aimed to identify novel FecA1-binding compounds in silico and then examined the effect of a predicted FecA1-binding compound on H. pylori SodB activity in vitro. Specifically, we demonstrated that nordihydroguaiaretic acid (NDGA) is a predicted FecA1-binding compound. NDGA reduced intracellular Fe(2+) levels in H. pylori and reduced SodB activity. Additionally, NDGA increased H2O2 sensitivity of H. pylori and increased the metronidazole (Mtz) sensitivity. The present study demonstrated that NDGA repressed SodB activity associated with the gastric mucosal-colonization via inhibition of intracellular Fe(2+) uptake by FecA1, suggesting that NDGA might be effective for the development of a novel eradication therapy.

Discovery and anti-cancer evaluation of two novel non-ATP-competitive FGFR1 inhibitors in non-small-cell lung cancer.

BACKGROUND: Fibroblast growth factor receptor 1 (FGFR1) is correlated closely with the occurrence and development of lung cancer. FGFR1 kinase inhibitors have exhibited significant therapeutic effects against non-small-cell lung cancer. Recently, non-ATP competitive FGFR1 inhibitors have attracted extensive attention due to their low side effects. METHODS: Caliper Mobility Shift Assay was used for FGFR1 inhibition test and kinase inhibitory mode study. Hoechst staining and Annexin V/PI staining were used to evaluate the cell apoptosis induction. Western blot were then performed to confirm the intracellular FGFR1 inhibition and apoptotic protein expression. Finally, the anti-tumor effect and mechanism of Af23 and Ad23 was evaluated in vivo. RESULTS: In this study, we designed, synthesized and discovered two novel non-ATP competitive FGFR1 inhibitors, Af23 and Ad23, using NDGA as a leading compound. They had IC50 values of 0.6 µM and 1.4 µM against FGFR1 kinase, respectively. The kinase inhibitory assay carried at different ATP concentrations showed that the FGFR1 inhibition mode of both Ad23 and Af23 was non-ATP-competitive. Further, Af23 and Ad23 significantly suppressed FGFR1 phosphorylation and cell proliferation in non-small-cell lung cancer (NSLCLC) H460 cells and induced cell apoptosis. Af23 and Ad23 also showed significant anti-tumor activity in the H460 xenograft mouse model, accompanied with the inhibition of FGFR1, ERK, and AKT phosphorylation without exhibiting toxicity. CONCLUSIONS: These results indicate that Ad23 and Af23 are potential agents for the treatment of non-small-cell lung cancer. This work also provides a structural lead for the design of new non-ATP-competitive FGFR1 inhibitors.

Phase I study of the novel Cdc2/CDK1 and AKT inhibitor terameprocol in patients with advanced leukemias.

PURPOSE: Inhibiting survivin and Cdc2 (CDK1) has preclinical anti-leukemic activity. Terameprocol is a small molecule survivin and Cdc2/CDK1 inhibitor that was studied in a Phase I dose-escalation trial. PATIENTS AND METHODS: Sixteen patients with advanced acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) were enrolled and 15 treated with Terameprocol in three dose cohorts intravenously three times per week for 2 weeks every 21 days. RESULTS: Patients had AML (n = 11), chronic myelogeneous leukemia in blast phase (CML-BP, n = 2) and one each T-cell acute lymphoblastic leukemia (T-ALL) and MDS. Four, five and six patients were treated at the 1000, 1500 and 2200 mg Terameprocol dose cohorts respectively. Common related treatment emergent adverse events (TEAE) were grade 1 or 2 headache, transaminitis and pruritus, with one grade 4 serious AE (SAE) of pneumonia. No dose limiting toxicity (DLT) was observed, however, due to other observed grade 3 TEAE the recommended phase 2 dose (RP2D) was determined at 1500 mg 3×/week for 2 weeks of a 21-day cycle. Partial remission and transfusion independence in a CML-BP patient (1500 mg cohort) and hematological improvement in erythroid (HI-E) and platelet lineage (HI-P) in an AML patient were observed. Five AML patients had stable disease greater/equal to 2 months. Pharmacodynamic studies showed a reduction of CDK1 and phospho-AKT protein expression. CONCLUSION: Terameprocol can be safely administered to advanced leukemia patients, sufficient drug exposure was obtained and clinical activity and biomarker modulation were observed.

NFATc3 pathway participates in the process that 15-LO/15-HETE protects pulmonary artery smooth muscle cells against apoptosis during hypoxia.

Hypoxia activates nuclear factor of activated T cells isoforms c3 (NFATc3), a Ca(2+)-dependent transcription factor in murine pulmonary arteries (PAs), and NFATc3 has been proved to be implicated in hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs) proliferation, but it remains unclear whether NFATc3 acts on the apoptosis of PASMCs, an important step in PAs remodeling. Our laboratory has demonstrated that 15-hydroxyeicosatetraenoic acid (15-HETE) is a key factor in hypoxia-induced PA remodeling and can increase PASMC intracellular Ca(2+) ([Ca(2+)](i)) in rats. It is possible that NFATc3 is related with the function of 15-HETE anti-apoptosis during hypoxia. Our results identified that NFATc3 was mainly localized in rat PASMCs and was upregulated in PAs during hypoxia-induced rat pulmonary hypertension (PH), while this effect was inhibited by administration of nordihydroguaiaretic acid (NDGA), a 15-lipoxygenase (15-LO) inhibitor. Moreover, hypoxia and exogenous 15-HETE promoted the expression and nuclear translocation of NFATc3 in PASMCs, which was inhibited by NDGA or small interfering RNA targeted to rat 15-LO1 or 15-LO2. Furthermore, endogenous 15-HETE induced by hypoxia and exogenous 15-HETE suppressed serum deprivation-induced loss of rat PASMCs survival and prevented annexin V binding, mitochondrial membrane potential depolarization, DNA nick end labeling and chromatin condensation. Although all these effects were suppressed after the cells were treated with cyclosporin A (a calcineurin/NFAT inhibitor), it aggravated the apoptosis induced by serum deprivation. Thus, all these results indicate that 15-HETE-mediated PASMCs anti-apoptosis in hypoxic PH via the Ca(2+)-NFATc3 pathway.

Nordihydroguaiaretic acid protects against high-fat diet-induced fatty liver by activating AMP-activated protein kinase in obese mice.

Nonalcoholic fatty liver disease, one of the most common causes of chronic liver disease, is strongly associated with metabolic syndrome. Nordihydroguaiaretic acid (NDGA) has been reported to inhibit lipoprotein lipase; however, the effect of NDGA on hepatic lipid metabolism remains unclear. We evaluated body weight, adiposity, liver histology, and hepatic triglyceride content in high-fat diet (HFD)-fed C57BL/6J mice treated with NDGA. In addition, we characterized the underlying mechanism of NDGA's effects in HepG2 hepatocytes by Western blot and RT-PCR analysis. NDGA (100 or 200mg/kg/day) reduced weight gain, fat pad mass, and hepatic triglyceride accumulation, and improved serum lipid parameters in mice fed a HFD for 8 weeks. NDGA significantly increased AMP-activated protein kinase (AMPK) phosphorylation in the liver and in HepG2 hepatocytes. NDGA downregulated the level of mature SREBP-1 and its target genes (acetyl-CoA carboxylase and fatty acid synthase), but, it upregulated expression of genes involved in fatty acid oxidation, such as peroxisome proliferator-activated receptor (PPAR)α, PPARγ coactivator-1, carnitine palmitoyl transferase-1, and uncoupling protein-2. The specific AMPK inhibitor compound C attenuated the effects of NDGA on expression of lipid metabolism-related proteins in HepG2 hepatocytes. The beneficial effects of NDGA on HFD-induced hepatic triglyceride accumulation are mediated through AMPK signaling pathways, suggesting a potential target for preventing NAFLD.

Cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate and nordihydroguaiaretic acid inhibit human Kv1.5 currents independently of lipoxygenase.

In humans, Kv1.5 (hKv1.5) channels conduct the ultra-rapid delayed rectifier K(+) current (I(Kur)) that is important for the repolarization of cardiac action potentials. We aimed at examining the effect of lipoxygenase inhibitors cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate (CDC), nordihydroguaiaretic acid (NDGA), and gossypol on hKv1.5 wild-type and mutant channels heterologously expressed in Chinese hamster ovary (CHO) cells, by use of the site-directed mutagenesis and whole-cell patch-clamp method. CDC and NDGA, but not gossypol, a structurally dissimilar inhibitor, reversibly inhibited hKv1.5 current in a concentration-dependent manner with IC(50) of 5.7 microM and 16.4 microM, respectively. The blockade evoked by both drugs was voltage-dependent between -20 and +10 mV (voltage range of channel opening). Moreover, this blocking action was found to progress with time during depolarizing voltage steps with a more rapid block at higher concentrations. CDC induced slight but significant delay of the deactivation rate. However, NDGA markedly slowed the deactivation time course, resulting in a tail crossover phenomenon. The recovery time constants from current block at repolarizing potentials for CDC and NDGA were 60.9 ms and 129.7 ms, respectively. Mutation of arginine 487 to valine (R487V) in the outer pore region of the channel significantly reduced the CDC action. These results demonstrate for the first time that CDC and NDGA block hKv1.5 channels by binding to the open state of the channels, independently of their effects on lipoxygenase activity. The putative binding site for CDC appears to be related to arginine 487 located in the outer pore region.

Conjugated linoleic acid-induced fat loss dependence on Delta6-desaturase or cyclooxygenase.

OBJECTIVE: To determine whether conjugated linoleic acid (CLA)-induced body fat loss is dependent upon metabolism of CLA by Delta6-desaturase, cyclooxygenase, or lipoxygenase. METHODS AND PROCEDURES: Mice were fed diets with or without CLA and inhibitors to either Delta6-desaturase (SC-26196), cyclooxygenase (aspirin), or lipoxygenase (nordihydroguaiaretic acid (NDGA)) for 2 weeks. Body fat percent, lean mass, fat pad weights, liver weight, and fatty acid concentrations were determined. A Delta6-desaturase index was calculated, and adipose tissue prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) concentrations were determined to confirm enzyme inhibition. RESULTS: Inhibition of Delta6-desaturase and cyclooxygenase were confirmed. CLA caused a loss of body fat (P < 0.001). The body fat loss was blocked (P = 0.08) by the Delta6-desaturase inhibitor at a dose that decreased (P < 0.05) the calculated index. Aspirin and NDGA had no effect on body fat and did not interact with CLA. DISCUSSION: Inhibition of Delta6-desaturase prevented CLA from being able to cause a body fat loss. Therefore, a desaturated metabolite of CLA appears to be involved in the CLA antiobesity effect. This effect of CLA does not seem dependent upon cyclooxygenase. Because lipoxygenase activity was not blocked by NDGA, we cannot draw conclusions about its importance in mediating the antiobesity effect of CLA.

Nordihydroguaiaretic acid and aspirin increase lifespan of genetically heterogeneous male mice.

The National Institute on Aging's Interventions Testing Program was established to evaluate agents that are purported to increase lifespan and delay the appearance of age-related disease in genetically heterogeneous mice. Up to five compounds are added to the study each year and each compound is tested at three test sites (The Jackson Laboratory, University of Michigan, and University of Texas Health Science Center at San Antonio). Mice in the first cohort were exposed to one of four agents: aspirin, nitroflurbiprofen, 4-OH-alpha-phenyl-N-tert-butyl nitrone, or nordihydroguaiaretic acid (NDGA). Sample size was sufficient to detect a 10% difference in lifespan in either sex,with 80% power, using data from two of the three sites. Pooling data from all three sites, a log-rank test showed that both NDGA (p=0.0006) and aspirin (p=0.01) led to increased lifespan of male mice. Comparison of the proportion of live mice at the age of 90% mortality was used as a surrogate for measurement of maximum lifespan;neither NDGA (p=0.12) nor aspirin (p=0.16) had a significant effect in this test. Measures of blood levels of NDGA or aspirin and its salicylic acid metabolite suggest that the observed lack of effects of NDGA or aspirin on life span in females could be related to gender differences in drug disposition or metabolism. Further studies are warranted to find whether NDGA or aspirin, over a range of doses,might prove to postpone death and various age-related outcomes reproducibly in mice.

Antigenotoxic effect of nordihydroguaiaretic acid against chlormadinone acetate-induced genotoxicity in mice bone-marrow cells.

Nordihydroguaiaretic acid (NDGA), a phenolic lignan, was tested for its antigenotoxic potential against chlormadinone acetate (CMA)-induced genotoxic damage in mice bone-marrow cells. Doses of about 22.50 mg/kg body weight of CMA were given along with 1, 5 and 10 mg/kg body weight of NDGA intraperitoneally. The treatment resulted in the reduction of sister chromatid exchanges and chromosomal aberrations induced by CMA, suggesting an antigenotoxic potential of NDGA. Earlier studies show that CMA generates reactive oxygen species, responsible for genotoxic damage. The free radical-scavenging property of NDGA is responsible for the reduction of genotoxic damage induced by CMA in mice bone-marrow cells.

Phase I clinical trial of repeat dose terameprocol vaginal ointment in healthy female volunteers.

OBJECTIVES: This safety study of terameprocol (also called M4N, EM-1421) daily vaginal application in healthy women explores its potential application as a microbicide in interrupting human immunodeficiency virus sexual transmission and additional interruption of human papillomavirus and herpes simplex virus transmission. METHODS: A double-blind placebo controlled phase I repeat dose tolerability and pharmacokinetic, crossover study of 90 mg terameprocol (2% w/w ointment) administered intravaginally for 7 consecutive days in healthy female subjects. The pharmacokinetics after administration was examined on days 1 and 7 of dosing. Subjects underwent vaginal examination following the 6-hour pharmacokinetic sample on day 7 of each study period. RESULTS: Recruitment started January 2006 and ended May 2006, and 14 subjects completed the study. Median age was 24 years. No treatment-related serious adverse events were reported, and there were a total of 17 treatment-emergent adverse events (AE) reported by 11 participants. The most common AE was headache. Terameprocol was not detectable in serum in pharmacokinetic samples. CONCLUSIONS: Terameprocol was well tolerated at a 90 mg dose (2% wt/wt) administered vaginally daily for 7 days. No serious adverse events occurred and any AEs were mild. The excellent safety profile supports future clinical trial to evaluate the application of intravaginal terameprocol in women.

Phase I/II clinical safety studies of terameprocol vaginal ointment.

OBJECTIVES: Terameprocol (M4N, EM-1421) is a novel transcription inhibitor that selectively interferes with HPV viral genes E6/E7 with Sp1-dependent promoters, and induces apoptosis by inactivation of the CDC2/cyclin B complex (maturation promoting factor) and production and phosphorylation of survivin. This trial was designed to define the maximum tolerated dose (MTD), dose-limiting toxicity and determine the pharmacokinetic profiles of intravaginal terameprocol in women with HPV-linked cervical squamous intraepithelial neoplasia. METHODS: An open label, dose escalation Phase I/II clinical trial enrolled women with biopsy confirmed CIN 1, 2 or 3. Terameprocol (45 or 90 mg) was physician-administered directly to the cervix uteri in 3 once weekly applications. The pharmacokinetics after administration were examined on Day 1 of dosing. Patients underwent colposcopic examinations, HPV testing, biomarker assessments, cytology and cervical punch biopsy. RESULTS: Recruitment ended March 30, 2006 and 7 patients were enrolled. Median age was 24 years. There were no serious adverse events (SAEs) and possible treatment-related Adverse Events (AEs) reported were mild and self-limiting. There was no detectable absorption of terameprocol from the vaginal ointment application. CONCLUSIONS: Terameprocol in 1% and 2% vaginal ointment use in Phase I/II trials with women with HPV-linked cervical intraepithelial neoplasia has an excellent safety profile, no SAEs reported and mild, self-limiting treatment-related AEs. There was no detectable absorption of terameprocol. These data support the continued evaluation of terameprocol in in vitro and animal efficacy models followed by definitive human Phase II clinical trials in CIN.

The anticancer activity of the transcription inhibitor terameprocol (meso-tetra-O-methyl nordihydroguaiaretic acid) formulated for systemic administration.

Terameprocol (meso-tetra-O-methyl nordihydroguaiaretic acid, formerly known as EM-1421 and M4N) is a semi-synthetic small molecule with antitumor activity occurring via selective targeting of Sp1-regulated proteins, including survivin and cdc2 that control cell cycle and apoptosis. Terameprocol is in clinical development as a site-specific transcription inhibitor in solid refractory tumors. The present studies were designed to investigate the in-vitro and in-vivo anticancer activity of terameprocol in a novel hydroxypropyl beta-cyclodextrin and polyethylene glycol solvent formulation (designated CPE) designed for safe parenteral administration. Terameprocol powder was dissolved in CPE (20% hydroxypropyl beta-cyclodextrin and 50% polyethylene glycol 300 or 30% hydroxypropyl beta-cyclodextrin and 25% polyethylene glycol 300) or dimethyl sulfoxide and used for in-vitro cell proliferation assays, and in human carcinoma xenograft studies using female athymic nude mice injected with SW-780 human bladder cells. Terameprocol (50 and 100 mg/kg), paclitaxel (5 mg/kg), terameprocol and paclitaxel or vehicle was administered intraperitoneally daily for 21 days. Stock solutions of the CPE formulation were stable for up to 12 months. Terameprocol CPE formulation showed concentration-dependent inhibition of HeLa and C33A cell proliferation, and was less toxic than terameprocol dimethyl sulfoxide formulation. The terameprocol CPE formulation showed no overt toxicities in tumor-bearing mice. Terameprocol alone reduced the rate of tumor growth, and a combination of terameprocol/paclitaxel reduced both the rate and extent of tumor growth. These preclinical results confirm the tumoricidal activity of terameprocol formulated in a solvent suitable for parenteral administration and suggest that terameprocol has improved efficacy when coadministered with paclitaxel.

The action of extracellular NAD+ on gluconeogenesis in the perfused rat liver.

In the rat liver NAD+ infusion produces increases in portal perfusion pressure and glycogenolysis and transient inhibition of oxygen consumption. The aim of the present work was to investigate the possible action of this agent on gluconeogenesis using lactate as a gluconeogenic precursor. Hemoglobin-free rat liver perfusion in antegrade and retrograde modes was used with enzymatic determination of glucose production and polarographic assay of oxygen uptake. NAD+ infusion into the portal vein (antegrade perfusion) produced a concentration-dependent (25-100 microM) transient inhibition of oxygen uptake and gluconeogenesis. For both parameters inhibition was followed by stimulation. NAD+ infusion into the hepatic vein (retrograde perfusion) produced only transient stimulations. During Ca2+-free perfusion the action of NAD+ was restricted to small transient stimulations. Inhibitors of eicosanoid synthesis with different specificities (indo-methacin, nordihydroguaiaretic acid, bromophenacyl bromide) either inhibited or changed the action of NAD+. The action of NAD+ on gluconeogenesis is probably mediated by eicosanoids synthesized in non-parenchymal cells. As in the fed state, in the fasted condition extracellular NAD+ is also able to exert two opposite effects, inhibition and stimulation. Since inhibition did not manifest significantly in retrograde perfusion it is likely that the generating signal is located in pre-sinusoidal regions.

Reversal of multidrug resistance by two nordihydroguaiaretic acid derivatives, M4N and maltose-M3N, and their use in combination with doxorubicin or paclitaxel.

PURPOSE: Multidrug resistance (MDR) continues to be a major obstacle for successful anticancer therapy. One of the principal factors implicated in MDR is the over expression of P-glycoprotein (Pgp), the product of the MDR1 gene. METHODS: Here we explore the possibility of using the transcription inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) to inhibit Sp1-regulated MDR1 gene expression and restore doxorubicin and paclitaxel sensitivity to multidrug resistant human cancer cells in vitro and in vivo. RESULTS: We found that M4N acted synergistically with doxorubicin and paclitaxel in inhibiting the growth of the cells in culture allowing significant dose reductions of both drugs. We observed no such synergism when M4N was used in combination with cisplatin, another chemotherapeutic agent, but not a Pgp substrate, as analyzed by the combination index and isobologram methods. Analysis of MDR1 mRNA and Pgp levels revealed that at sublethal doses, M4N inhibited MDR1 gene expression in the multidrug resistant NCI/ADR-RES cells and reversed the MDR phenotype as measured by Rhodamine-123 retention. In addition, M4N was found to inhibit doxorubicin-induced MDR1 gene expression in drug sensitive MCF-7 breast cancer cells. CONCLUSIONS: M4N and maltose-tri-O-methyl nordihydroguaiaretic acid (maltose-M3N), a water-soluble derivative of NDGA, were also able to reverse the MDR phenotype of the tumor cells in a xenograft model system and combination therapy with M4N or maltose-M3N and paclitaxel was effective at inhibiting growth of these tumors in nude mice.

Anti-inflammatory effects of specific cyclooxygenase 2,5-lipoxygenase, and inducible nitric oxide synthase inhibitors on experimental autoimmune anterior uveitis (EAAU).

PURPOSE: Inflammation, in general, causes the release of a variety of inflammatory mediators that in turn induce cyclooxygenase (COX) 2, nitric oxide synthase (iNOS) and 5-lipoxygense (LP) synthesis, producing large amounts of inflammatory prostaglandins (PG), nitric oxide (NO), and leukotriene (LT) B4. Therefore, inhibition of these enzymes may abrogate intraocular inflammation in experimental autoimmune anterior uveitis (EAAU). METHODS: Lewis rats were immunized with melanin-associated antigen (MAA) isolated from bovine iris and ciliary body. These animals were divided into three groups. The first group of rats received subcutaneous injection of COX 2 inhibitor CS 236 at different time points. The second and third groups of animals received subcutaneous aminoguanidine (AG), an iNOS inhibitor, and nordihydroguaiaretic acid (NDGA), a 5-LP inhibitor, respectively. Control animals received vehicle. Rat eyes were examined daily by slit-lamp biomicroscopy from Day 7 to 30 post injection for uveitis. Animals were also sacrificed at various time points for histologic analysis. RESULTS: Control animals developed severe EAAU in both eyes. The disease started in these animals on Day 12 post immunization and lasted for ten days. Interestingly, CS 236, a potent COX 2 inhibitor, completely abrogated EAAU when the animals were treated daily from the Day 0 to 14 or Day 0 to 20 after MAA injection. Furthermore, daily CS 236 treatment after the onset of EAAU (Day 14-20) significantly reduced the severity (both clinical and histologic) of EAAU and shortened the duration of disease. iNOS inhibitor (AG) and 5-LP inhibitor (NDGA) partially attenuated EAAU. CONCLUSIONS: Our results show that EAAU was partially attenuated by AG and NDGA. Interestingly, CS 236, a potent COX 2 inhibitor, completely inhibited EAAU in male Lewis rats most likely by inhibiting the initial phase and onset of the disease.

Systemic treatment with tetra-O-methyl nordihydroguaiaretic acid suppresses the growth of human xenograft tumors.

PURPOSE: We have previously shown that the transcriptional inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) induces growth arrest in tumor cells and exhibits tumoricidal activity when injected intratumorally into tumor cell explants in mice. The experiments reported here were designed to determine whether M(4)N can be given systemically and inhibit the growth of five different human xenograft tumors. EXPERIMENTAL DESIGN: Nude (nu/nu) mice bearing xenografts of each of five human tumor types (i.e., hepatocellular carcinoma, Hep 3B; prostate carcinoma, LNCaP; colorectal carcinoma, HT-29; breast carcinoma, MCF7; and erythroleukemia, K-562) were treated with M4N given i.v. or i.p. in a Cremophor EL-based solvent system or orally in a corn oil based diet. Tumors from the treated animals were measured weekly and analyzed for the expression of the Cdc2 and survivin genes, both previously shown to be down-regulated by M4N. RESULTS: Systemic M4N treatment suppressed the in vivo growth of xenografts in each of the five human tumor types. Four of the five tumor models were particularly sensitive to M4N with tumor growth inhibitions (T/C values) of < or = 42%, whereas the fifth, HT-29, responded to a lesser extent (48.3%). Growth arrest and apoptosis in both the xenograft tumors and in the tumor cells grown in culture were accompanied by reductions in both Cdc2 and tumor-specific survivin gene expression. Pharmacokinetic analysis following oral and i.v. administration to ICR mice indicated an absolute bioavailability for oral M4N of approximately 88%. Minimal drug-related toxicity was observed. CONCLUSION: These preclinical studies establish that when given systemically, M4N can safely and effectively inhibit the growth of human tumors in nude mice.

Naturally occurring lignans efficiently induce apoptosis in colorectal tumor cells.

Plant-derived lignans caused cell loss by apoptosis in colorectal adenoma and carcinoma cells. Nordihydroguaiaretic acid (NDGA), commonly used for the inhibition of lipoxygenase isoenzymes, showed the strongest growth inhibition with an IC50 of 1.9+/-0.5 microg followed by epiashantin (IC50=9.8+/-4.5 microM) and arctigenin (IC50=16.5+/-8.5 microM). The lignans caused a time- and dose-dependent loss of mitochondrial membrane potential (MMP), down regulation of the anti-apoptotic protein bcl(xl) and an increase of the apoptotic index. The time interval until loss of MMP and down modulation of bcl(xl) became evident correlated with the efficiency of growth inhibition by NDGA, epiashantin and yangambin. Bcl2 and caspase 3 were not involved. NDGA also induced a shift of the culture population to the G2/M phase of the cell cycle. With respect to these results, naturally occurring lignans could be useful in the therapy and chemoprevention of colorectal tumors.