Recent studies have identified myeloid-derived suppressor cells (MDSCs) that are potent suppressors of tumor immunity and therefore a significant impediment to cancer immunotherapy. It has been reported that MDSCs are generated by malignant diseases or inflammation. However, no systematic studies in patients have been described. In order to clinically characterize MDSCs, we tested PBMCs from patients with various types of cancer including cholangiocellular, hepatocellular and pancreatic carcinoma, esophageal, gastric and colorectal cancer, breast cancer and thyroid cancer, and GIST, and those from normal volunteers using flow cytometry analysis. A significant increase was seen in the percentages of MDSCs in PBMCs from patients compared with normal volunteers. Among these patients, MDSC level was higher in patients with cancer of the digestive system and patients with breast cancer compared with normal volunteers. MDSC level was significantly and inversely correlated to stimulation indices (SI) of PHA-blastogenesis of lymphocytes and serum concentration of total protein, and positively correlated to neutrophil count. MDSC percentage in patients with gastric and colorectal cancer was also significantly correlated to neutrophil count and inversely correlated with lymphocyte count, and showed highly significant correlation to neutrophil/lymphocyte rate (NLR). In patients with breast cancer, MDSC levels in preoperative patients was significantly increased compared to normal volunteers and significantly decreased in postoperative patients. Thus, it is clear that MDSCs are increased in patients with cancer and closely related to suppression of cell-mediated immune responses. These data also suggest that they are related to chronic inflammation and that their levels are increased further in the terminal stages of patients whose nutritional status is impaired as observed in hypoproteinemia. MDSC levels have also been shown to decrease after removal of tumors in patients with breast cancer.

Differential screening of the genes obtained from cDNA libraries of primary neuroblastomas (NBLs) between the favorable and unfavorable subsets has identified a novel gene BCH motif-containing molecule at the carboxyl terminal region 1 (BMCC1). Its 350 kDa protein product possessed a Bcl2-/adenovirus E1B nineteen kDa-interacting protein 2 (BNIP2) and Cdc42GAP homology domain in the COOHterminus in addition to P-loop and a coiled-coil region near the NH 2 -terminus. High levels of BMCC1 expression were detected in the human nervous system as well as spinal cord, brain and dorsal root ganglion in mouse embryo. The immunohistochemical study revealed that BMCC1 was positively stained in the cytoplasm of favorable NBL cells but not in unfavorable ones with MYCN amplification. The quantitative real-time reverse transcription-PCR using 98 primary NBLs showed that high expression of BMCC1 was a significant indicator of favorable NBL. In primary culture of newborn mice superior cervical ganglion (SCG) neurons, mBMCC1 expression was downregulated after nerve growth factor (NGF)-induced differentiation, and upregulated during the NGF-depletion-induced apoptosis. Furthermore, the proapoptotic function of BMCC1 was also suggested by increased expression in CHP134 NBL cells undergoing apoptosis after treatment with retinoic acid, and by an enhanced apoptosis after depletion of NGF in the SCG neurons obtained from newborn mice transgenic with BMCC1 in primary culture. Thus, BMCC1 is a new member of prognostic factors for NBL and may play an important role in regulating differentiation, survival and aggressiveness of the tumor cells.

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Background— The acetylcholine-activated K + current ( I K,ACh ) is a novel candidate for atrial-specific antiarrhythmic therapy. The present study investigates the involvement of I K,ACh in atrial fibrillation (AF) using NTC-801, a novel potent and selective I K,ACh blocker. Methods and Results— The effects of NTC-801, substituted 4-(aralkylamino)-2,2-dimethyl-3,4-dihydro- 2H -benzopyran-3-ol, on I K,ACh and other cardiac ionic currents ( I Na , I CaL , I to , I Kur , I Kr , I Ks , I Kl , I KATP , and I f ) and on atrial and ventricular action potentials were examined in vitro. NTC-801 potently inhibited carbachol-induced I K,ACh in guinea pig atrial cells and the GIRK1/4 current in Xenopus oocytes with IC 50 values of 5.7 and 0.70 nmol/L, respectively. NTC-801 selectively inhibited I K,ACh >1000-fold over other cardiac ionic currents. NTC-801 (10 to 100 nmol/L) reversed the action potential duration (APD 90 ) shortened by carbachol or adenosine in atrial cells, whereas it did not affect APD 90 at 100 nmol/L in ventricular cells. Antiarrhythmic effects of NTC-801 were evaluated in 3 AF models in vivo. NTC-801 significantly prolonged atrial effective refractory period without affecting ventricular effective refractory period under vagal nerve stimulation. NTC-801 dose-dependently converted AF to normal sinus rhythm in both vagal nerve stimulation–induced (0.3 to 3 μg · kg −1 · min −1 IV) and aconitine-induced (0.01 to 0.1 mg/kg IV) models. In a rapid atrial pacing model, NTC-801 (3 μg · kg −1 · min −1 IV) significantly decreased AF inducibility with a prolonged atrial effective refractory period that was frequency-independent. Conclusions— A selective I K,ACh blockade induced by NTC-801 exerted anti-AF effects mediated by atrial-selective effective refractory period prolongation. These findings suggest that I K,ACh may be important in the development and maintenance of AF.

Although a causal relationship between inflammation and innate immunity of cancer is more widely accepted today, many of the precise cell mechanisms mediating this relationship have not been elucidated. Th17 cells, which produce the proinflammatory cytokine interleukin 17 (IL-17), have been recognized as one of the key factors in the regulation of inflammatory bowel disease and rheumatoid arthritis. This study demonstrated that, in patients with various types of gastrointestinal cancer, IL-17 production was correlated with myeloid-derived suppressor cell (MDSC) levels and with markers for nutritional impairment, immune suppression and chronic inflammation. IL-17 was significantly higher in patients with various types of gastrointestinal cancer compared to normal volunteers. In addition, IL-17 levels were significantly correlated with neutrophil counts and the neutrophil/lymphocyte ratio (NLR) and significantly inversely correlated with cell-mediated immune response indicators [lymphocyte phytohemagglutinin (PHA)-blastogenesis and IL-12 induction] and patient nutritional status (prealbumin levels). Circulating MDSC levels were significantly correlated with IL-17 production. These results suggest that, in human gastrointestinal cancers, chronic inflammation involving IL-17 may be an important mechanism contributing to disease progression through enhancement of immune suppression or cachexia. Controlling the activation of Th17 cells may prove to be a valuable strategy for the treatment of gastrointestinal cancer patients.

The complement system, a part of the innate immune system, can be activated via three different pathways. In the alternative pathway, a factor D (FD) plays essential roles in both the initiation and the amplification loop and circulates as an active form. Mannose-binding lectin–associated serine proteases (MASPs) are key enzymes of the lectin pathway, and MASP-1 and/or MASP-3 are reported to be involved in the activation of FD. In the current study, we generated mice monospecifically deficient for MASP-1 or MASP-3 and found that the sera of the MASP-1–deficient mice lacked lectin pathway activity, but those of the MASP-3–deficient mice lacked alternative pathway activity with a zymogen FD. Furthermore, the results indicate that MASP-3 but not MASP-1 activates the zymogen FD under physiological conditions and MASP-3 circulates predominantly as an active form. Therefore, our study illustrates that, in mice, MASP-3 orchestrates the overall complement reaction through the activation of FD.

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BackgroundPulmonary arterial hypertension is often associated with connective tissue disease. Although there are some animal models of pulmonary hypertension, an autoimmune disease-based model has not yet been reported. MRL/lpr mice, which have hypergammaglobulinemia, produce various autoimmune antibodies, and develop vasculitis and nephritis spontaneously. However, little is known about pulmonary circulation in these mice. In the present study, we examined the pulmonary arterial pressure in MRL/lpr mice.Methods and resultsWe used female MRL/lpr mice aged between 12 and 14 weeks. Fluorescent immunostaining showed that there was no deposition of immunoglobulin or C3 in the lung tissue of the MRL/lpr mice. Elevation of interferon-γ and interleukin-6 was recognized in the lung tissue of the MRL/lpr mice. Right ventricular systolic pressure, Fulton index and the ratio of right ventricular weight to body weight in the MRL/lpr mice were significantly higher than those in wild type mice with same background (C57BL/6). The medial smooth muscle area and the proportion of muscularized vessels in the lung tissue of the MRL/lpr mice were larger than those of the C57BL/6 mice. Western blot analysis demonstrated markedly elevated levels of prepro-endothelin-1 and survivin as well as decreased endothelial nitric oxide synthase phosphorylation in the lung tissue of the MRL/lpr mice. Terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling assay showed the resistance against apoptosis of pulmonary arterial smooth muscle cells in the MRL/lpr mice.ConclusionWe showed that MRL/lpr mice were complicated with pulmonary hypertension. MRL/lpr mice appeared to be a useful model for studying the mechanism of pulmonary hypertension associated with connective tissue diseases.