Macrophage migration inhibitory factor (MIF) has been linked to fundamental processes such as control of cell proliferation, cell survival, angiogenesis, and tumor progression. The expression of MIF has been reported in several tumors. However, the precise role of MIF in tumor cells remains unclear. In the present study, we investigated the expression pattern and the function of MIF in neuroblastoma. Our results showed that intracellular MIF was upregulated in neuroblastoma tumor tissues and cell lines. MIF protein expression significantly correlated with the grade of tumor differentiation. In addition, we found that MIF induced a significant dosedependent increase of vascular endothelial growth factor and interleukin-8 secretion. We also observed that an increased MIF expression level correlated with N-Myc protein (the N-myc oncogene product) expression in neuroblastoma tissues. MIF increased the expression of N-myc mRNA and N-Myc protein and induced N-Myc translocation from the cytoplasm to nucleus in neuroblastoma cell lines. MIF-induced N-Myc expression was found to be dependent on ERK signaling pathways. The inhibition of ERK activation reduced MIF-mediated NMyc expression. These results suggest that MIF may contribute to the progression of neuroblastoma by (a) inducing N-Myc expression and (b) upregulating the expression of angiogenic factors.

Taking advantage of efficient affinity extraction by surface-functionalized magnetic nanoparticles (MNPs) and accurate MALDI-TOF MS readout, we present a multiplexed immunoassay for simultaneous enrichment and quantitation of multiple disease-associated antigens, serum amyloid A (SAA), C-reactive protein (CRP), and serum amyloid P (SAP) from human serum. To obtain reproducible MALDI signal response with direct on-MNP detection, the seed-layer method improved homogeneity of the cocrystallization of MNPs and captured antigens. Our methodology demonstrated good quantitation linearity of targeted analytes (R(2) approximately 0.97) with reduced signal variation (RSD < 10%). The lower limit of quantitation is in the nanogram level with overall assay precision (intraday, 7.0%; interday, 11.3%) and accuracy (intraday, 6.3%; interday, 17.5%) including steps of nanoprobe extraction and MALDI-TOF MS analysis. This triplexed immunoassay showed overexpression of SAA and CRP in patients with cardiac catheterization or gastric cancer (P < 0.05), consistent with single-analyte ELISA and previous studies. Compared to the determination of disease onset by single protein quantitation, our multiplexed immunoassay revealed a distinct triplexed pattern in the control group, patients with gastric cancer, and cardiac catheterization. On the basis of the advantages of flexibility in nanoprobe preparation, high specificity and sensitivity, and rapid screening by MALDI-TOF MS, this platform may provide a new methodology for disease diagnosis.

We have shown previously that lignocaine inhibits the upregulation of inducible nitric oxide synthase (iNOS), a crucial factor that initiates the systemic inflammatory response during sepsis, possibly through voltage-sensitive sodium channels (VSSC). Toll-like receptor-4 (TLR-4), nuclear factor (NF)-kappaB and mitogen activated protein kinases (MAPKs) participate in the upstream regulation of iNOS expression induced by endotoxin. In the present study, we investigated the effects of lignocaine in the regulation of the expression of these enzymes. The role of VSSC in the effects of lignocaine was also investigated. Confluent murine macrophages (RAW264.7 cells) were randomized to receive lipopolysaccharide (LPS; 100 ng/mL), LPS + lignocaine (50 micromol/L), LPS + tetrodotoxin (TTX; 1 micromol/L; a VSSC inhibitor), LPS + lignocaine + veratridine (Ver; 50 micromol/L; a VSSC activator) or LPS + TTX + Ver. After reacting with LPS for 0, 15, 30, 45 and 60 min, cell cultures were harvested and enzyme expression was evaluated. We found that LPS significantly increased the concentrations of TLR-4, NF-kappaB and MAPKs, including extracellular regulated kinase (ERK), c-jun N-terminal kinase (JNK) and p38 MAPK, in activated macrophages. Lignocaine and TTX significantly attenuated the effects of LPS on TLR-4, NF-kappaB, ERK and p38 MAPK expression, but not on JNK. Veratridine mitigated the effects of lignocaine and TTX. These data demonstrate that lignocaine has significant inhibitory effects on the activation of TLR-4, NF-kappaB and MAPKs in activated macrophages. Moreover, these effects involve VSSC.

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