A novel minimal residual disease model of neuroblastoma in mice.

INTRODUCTION: Patients with high-risk neuroblastoma rarely succumb to their primary tumor but rather from relapsed metastatic disease after surgery. We, therefore, sought to create an in vivo model of minimal residual disease (MRD), which clinically replicates tumor recurrence and metastasis after surgical resection. METHODS: Neuroblastoma cell lines CHLA-255, CHLA-136, and SH-SY5Y were used. After establishing orthotopic xenografts, mice were divided into control tumor group (sham operation at 14days) and tumor resection group (resection at 14days). Mice were monitored by bioluminescent imaging and sacrificed when institutional criteria for euthanasia were met. RESULTS: In the CHLA-255 and CHLA-136 cell lines, mice experienced significantly longer survival following tumor resection (p<0.007). There was no survival benefit seen in the SH-SY5Y cell line (p=0.29). Bioluminescent imaging demonstrated metastatic disease in 100% of all tumor resection mice and varying rates of metastasis in control mice (4 of 5 CHLA-255, 2 of 4 CHLA-136, and 7 of 7 SH-SY5Y). CONCLUSION: In this study, we describe a novel neuroblastoma model of MRD in mice. This MRD model serves as an innovative means to test preclinical therapies as well as elucidate mechanisms of metastatic disease in experimental neuroblastoma.

Liquid chromatography method for quantifying D-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (D-threo-PPMP) in mouse plasma and liver.

A high-performance liquid chromatography (HPLC) method was developed to measure levels of d-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (d-threo-PPMP) in mouse plasma and liver. d-threo-PPMP was measured by HPLC with a Luna Pheny-Hexyl column (5 microm, 250 mm x 4.6 mm) employing UV detection at 210 nm using a mobile phase of potassium phosphate buffer (20mM, pH 3.0)-acetonitrile in a 45:55 (v/v) ratio. d-threo-1-phenyl-2-pentadecanoylamino-3-morpholino-1-propanol (PC15MP) was employed as an internal standard (IS). The lower limit of quantitation (LLOQ) was 0.3 microg/ml. The assay was linear over a concentration range of 0.3-10 microg/ml, with acceptable precision and accuracy. Assayed in plasma, the intra- and inter-day validation for all coefficients of variation (R.S.D.%) were found less than 15%. The method was applied to samples from athymic (nu/nu) mice treated with d-threo-PPMP by intraperitoneal injection. d-threo-PPMP levels of approximately 10-20 microg/ml ( approximately 20-40 microM) in plasma and approximately 45 microg/g in liver were obtained. The present method can be used to quantify d-threo-PPMP in mice for bioavailability and dose-response studies.

Suppressive effect of inducible nitric oxide synthase (iNOS) expression by the methanol extract of Actinodaphne lancifolia.

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has played a crucial role in various pathophysiological processes including inflammation and carcinogenesis. Therefore, the inhibitors of NO synthesis or iNOS gene expression have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for iNOS inhibitors from natural products we have evaluated indigenous Korean plant extracts using an assay for inhibition of nitric oxide formation on lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells. As a result, the methanolic stem extract of Actinodaphne lancifolia showed an inhibitory activity of NO production in a dose-dependent manner (IC50 = 2.5 microg/ml). Additional study demonstrated that the extract of Actinodaphne lancifolia significantly suppressed the iNOS protein and gene expression in a dose-dependent manner. These results suggest that Actinodaphne lancifolia could be a potential candidate for developing an iNOS inhibitor from natural products. Further elucidation of active principles for development of new cancer chemopreventive and/or anti-inflammatory agents could be warranted.

Inhibitory phenolic amides on lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells from Beta vulgaris var. cicla seeds.

Four phenolic compounds were isolated from Beta vulgaris L. var. cicla L. (Chenopodiaceae). These isolated compounds were identified as N-cis-feruloyl 3-O-methyldopamine (1), N-cis-feruloyl tyramine (2), N-trans-feruloyl 3-O-methyldopamine (3), N-trans-feruloyl tyramine (4), respectively, by spectroscopic analysis. The phenolic amides 1-4 exhibited modest inhibitory activity on LPS-activated nitric oxide production dose-dependently in RAW 264.7 cells.

TRAIL, a mighty apoptosis inducer.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a membrane-bound cytokine molecule that belongs to the family of tumor necrosis factor (TNF). TRAIL has been shown to be a potent apoptosis inducer in a wide variety of cancer cells in vitro and to limit tumor growth efficiently in vivo without damaging normal tissues. These features have focused considerable attention on TRAIL as a potential therapeutic agent to treat human cancers. Recent data also suggest the implication of TRAIL in a natural defense mechanism since its abrogation results in certain autoimmune disorders. This review will summarize recent progress in TRAIL research, including understanding of apoptotic signaling, regulation of TRAIL action, and possible therapeutic applications.

Eugenol suppresses cyclooxygenase-2 expression in lipopolysaccharide-stimulated mouse macrophage RAW264.7 cells.

Inducible cyclooxygenase (COX-2) has been implicated in the processes of inflammation and carcinogenesis. Thus, the potential COX-2 inhibitors have been considered as anti-inflammatory or cancer chemopreventive agents. In this study, the methanolic extract of the cortex of Eugenia caryophyllata Thunberg (Myrtaceae) was found to potently inhibit the prostaglandin E(2) production in lipopolysaccharide (LPS)-activated mouse macrophage RAW264.7 cells (98.3% inhibition at the test concentration of 10 microg/ml). Further, hexane-soluble layer was the most active partition compared to ethyl acetate, n-butanol, and water-soluble parts. By bioassay-guided fractionation of hexane-soluble partition, eugenol was isolated and exhibited a significant inhibition of PGE(2) production (IC(50) = 0.37 microM). In addition, eugenol suppressed the cyclooxygenase-2 (COX-2) gene expression in LPS-stimulated mouse macrophage cells. On the line of COX-2 playing an important role in colon carcinogenesis further study was designed to investigate the effect of eugenol on the growth and COX-2 expression in HT-29 human colon cancer cells. Eugenol inhibited the proliferation of HT-29 cells and the mRNA expression of COX-2, but not COX-1. This result suggests that eugenol might be a plausible lead candidate for further developing the COX-2 inhibitor as an anti-inflammatory or cancer chemopreventive agent.