Abstract. Sepsis remains the most common cause of death in intensive care units in the USA, with a current estimate of at least 750,000 cases per year, and 215,000 deaths annually. Despite extensive research still we do not quite understand the cellular and molecular mechanisms that are involved in triggering and propagation of septic injury. Endotoxin (lipopolysaccharide from Gram-negative bacteria, or LPS) has been implicated as a major cause of this syndrome. Inflammatory shock as a consequence of LPS release remains a serious clinical concern. In humans, inflammatory responses to LPS result in the release of cytokines and other cell mediators from monocytes and macrophages, which can cause fever, shock, organ failure and death. A number of different approaches have been investigated to try to treat and/or prevent the septic shock associated with infections caused by Gram-negative bacteria, including blockage of one or more of the cytokines induced by LPS. Recently several novel amphipathic compounds have been developed as direct LPS antagonists at the LPS receptor, TLR4. This review article will outline the current knowledge on the TLR4-LPS synthesis and discuss the signaling, in vitro pre-clinical and in vivo clinical evaluation of TLR4 antagonists and their potential use in sepsis and a variety of diseases such as atherosclerosis as well as hepatic and renal malfunction.

Lanthanide ions, Ln(III), are known functional mimics of Ca(II) ions and have been shown to affect the bone remodeling cycle. Exploiting this disruption to the bone remodeling cycle has potential for the treatment of bone density disorders, such as osteoporosis. In an effort to find new orally active agents for these disorders, a series of Ln(III) containing complexes incorporating small, non-toxic, bidentate pyrone and pyridinone ligands have been synthesized and characterized (LnL(3), Ln = La, Eu, Gd, Tb, Yb, L = 3-oxy-2-methyl-4-pyrone (ma(-)), 3-oxy-2-ethyl-4-pyrone (ema(-)), 3-oxy-1,2-dimethyl-4-pyridinone (dpp(-)) and 3-oxy-2-methyl-4(1H)-pyridinone (mpp(-))). Preliminary biological analysis included cytotoxicity, cell uptake and bidirectional transport studies in Caco-2 cells and in vitro hydroxyapatite (HA) binding studies. The proportion of intact compounds bound to HA was calculated based on determination of Ln(III) concentration by ICP-MS and by UV-vis spectrophotometric assay of the proligand in solution. The LnL(3) species were found to have IC(50) values at least 6 times greater than that of cisplatin, >or= 98% HA-binding capacity, and permeability coefficients in the moderate range. La(dpp)(3) was ascertained to be the lead compound for the treatment of bone density disorders with the highest percentage cell uptake of 9.07 +/- 2.33% and the highest preliminary P(app) value of 3.54 +/- 2.86 x 10(-6) cm s(-1) compared to the other LnL(3) complexes tested.

-Purpose. Oral drug development had been hindered by the bioavailability issue despite vast market popularity. Lipid excipients had shown to enhance bioavailability of a number of reformulated hydrophobic oral drugs, yet the underlying mechanisms of action by lipids are still unclear. One proposed mechanism is that lipid excipients could facilitate drug uptake by altering the activities of apical membrane intestinal efflux transporters. Thus, this study aimed to investigate the effects of 1-monopalmitin, 1-monoolein and 1-monostearin on the efflux activity and protein expression of multidrug resistance-associated protein 2 (MRP2) in vitro. Methods. The 24-hour non-cytotoxic ranges of these monoglycerides were first determined using MTS and LDH assays in Caco-2 cells. Then, both accumulation and bidirectional transport studies were conducted using 10 μM rhodamine 123 (Rh123) and 10 nM estradiol 17 β-D-glucuronide (E 2 17βG), respectively, to assess the functional activities of MRP2. 50 µM MK-571, a specific MRP1 and MRP2 inhibitor, was used as the positive control in both studies. Western blotting was followed to determine the effect of these monoglycerides on MRP2 protein expression. Results. Caco-2 cells were viable when treated with 1-monopalmitin, 1-monostearin and 1-monoolein at concentrations equal or less than 1000 µM, 1000 µM and 500 µM, respectively. Cells treated with 1-monoplamitin, 1-monostearin, 1-monoolein and MK571 resulted in significant increases in Rh123 accumulation and decreases in E 2 17βG efflux ratio compared to the control (medium treated only). MRP2 protein expressions in 1-monopalmitin and 1-monoolein treated cells were decreased by 19% and 35% compared to the control; however, there was no change of MRP2 protein expression in 1-monostearin treated cells. Conclusions. These findings suggested that 1-monoolein, 1-monostearin and 1-monopalmitin could attenuate the activity of MRP2 and possibly other efflux transporters in Caco-2 cells. The reduction of efflux activity of MRP2 by 1-monoolein treatment could be partially accounted by the non-specific down-regulation of MRP2 protein expression.

Abstract4T1 murine mammary carcinoma cells implanted in syngeneic Balb/c mice are increasingly being used in metastasis research, with some groups using this model to study tumor-induced accumulation of bone marrowderived cells in metastatic target organs. Bone marrow-derived cells (including CD11bþ Gr-1 þ myelomonocytic cells) are thought to modify the local lung microenvironment to facilitate subsequent colonization by metastatic tumor cells. While quantification of metastatic 4T1 tumor cells in various tissues can be done using ex vivo colony-forming assays, detection of metastatic 4T1 cells is often facilitated by expressing fluorescent proteins in the tumor cells prior to implantation. We found that Balb/c mice mount a potent immune response against 4T1 cells expressing green fluorescent protein (GFP) that includes the generation of anti-GFP antibodies in the circulation. Importantly, the number of bone marrow-derived CD11b GFP-expressing tumor cells are not recommended to study the metastatic process in Balb/c mice beyond the first few days of implantation (2) because GFP is immunogenic in this mouse strain (3-5). We found that a population of 4T1 cells that were more than 96% GFP þ produced tumors with less than 10% GFP þ cells within 3 weeks of orthotopic implantation into Balb/c mice. Furthermore, the mean fluorescence intensity of the surviving GFP þ cells was several orders of magnitude lower than the in vitro parental population (data not shown). These observations indicate a strong in vivo selection for the survival and proliferation of 4T1 cells that express low levels of GFP and/or do not express GFP. Indeed, we identified anti-GFP IgG antibodies in the plasma of Balb/c mice implanted with 4T1-GFP cells (Fig. 1A) (Fig. 1B).Colony-forming assays are well established for quantifying therapeutically relevant metastatic 4T1 tumor cells with greater sensitivity than flow cytometry-based quantification of fluorescent tumor cells. Clonogenic 4T1 tumor cells could be observed in the lungs within 14 days of orthotopic tumor implant, and the number of clonogenic tumor cells in the lungs of 4T1 tumor-bearing mice was 9-fold higher than in mice implanted with 4T1-GFP tumor cells after 21 days (Fig. 1C). We found similar results with 4T1 cells expressing DsRed, a red fluorescent protein, suggesting that Balb/c mice may mount immune responses against a variety of fluorescent proteins. The role of matrix metalloproteinase 9 (MMP-9) derived from CD11b þ Gr-1 þ cells in modulating the lung environment of tumor-bearing mice as described by Yan and colleagues is an important finding. However, caution is warranted when studying the in vivo effects of GFP-expressing tumor cells on immunomodulatory cells (such as CD11b þ Gr-1 þ cells) and metastases in light of the substantial immune response mounted by Balb/c mice against GFPexpressing tumor cells.

No abstract