Omega-3 fatty acids regulate gene expression levels differently in subjects carrying the PPARα L162V polymorphism

Omega-3 fatty acids (FAs) are natural ligands of the peroxisome proliferator-activated receptor-α (PPARα), a nuclear receptor that modulates expression levels of genes involved in lipid metabolism. The L162V polymorphism of the PPARα gene is associated with a deteriorated metabolic profile. We postulate that subjects carrying the PPARα-V162 allele exhibit differences in the expression of PPARα and its target genes after incubation with omega-3 FAs compared with L162 homozygotes. Peripheral blood monocytes from six men carrying the PPARα-V162 allele paired for age and for body mass index with six L162 homozygotes were differentiated into macrophages and activated with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or mixtures of EPA:DHA. Data demonstrates that gene expression levels of PPARα and apolipoprotein AI (APOA1) were significantly lower for carriers of the PPARα-V162 allele compared to L162 homozygotes after the addition of DHA and a mixture of EPA:DHA. Additionally, lipoprotein lipase (LPL) gene expression displayed a tendency to be lower in the PPARα L162V polymorphism subgroup after the addition of a mixture of EPA:DHA. Consequently, individuals carrying the PPARα-V162 allele may demonstrate inferior improvements in their lipid profile due to alterations in gene expression rates in response to omega-3 FA supplementation.     

The nonclassical major histocompatibility complex molecule Qa-2 protects tumor cells from NK cell- and lymphokine-activated killer cell-mediated cytolysis

The cytotoxic activity of NK cells is regulated by class I MHC proteins. Although much has been learned about NK recognition of class I autologous targets, the mechanisms of NK self-tolerance are poorly understood. To examine the role of a nonpolymorphic, ubiquitously expressed class Ib Ag, Q9, we expressed it on class I-deficient and NK-sensitive B78H1 melanoma. Presence of this Qa-2 family member on tumor cells partially protected targets from lysis by bulk lymphokine-activated killer (LAK) cells. H-2K(b)-expressing B78H1 targets also reduced LAK cell activity, while H-2D(b) offered no protection. Importantly, blocking with F(ab')(2) specific for Q9 or removal of this GPI-attached molecule by phospholipase C cleavage restored killing to the level of vector-transfected cells. Experiments with LAK cells derived from H2(b) SCID and B6 mice established that NK1.1(+)TCR(-) NK and NK1.1(+)TCR(+) LAK cells were the prevalent cytolytic populations inhibitable by Q9. Treatment of mice with poly(I:C) also resulted in generation of Q9-regulated splenic cytotoxicity. LAK cells from different mouse strains responded to Q9, suggesting that the protective effect of this molecule is not detectably influenced by Ly49 polymorphisms or the presence/absence of Q9 in NK-harboring hosts. We propose that Q9 expressed on melanoma cells serves as a ligand for yet unidentified NK inhibitory receptor(s) expressed on NK1.1(+) NK/T cells.     

Multinuclear NMR spectroscopy and antitumor activity of novel platinum(II) complexes with 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines

Novel platinum(II) complexes with 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines have been synthesized and characterized by infrared and multinuclear magnetic resonance spectroscopic techniques (1H, 13C, 15N, 195Pt). The complexes are of two types: [PtCl2(L)2] and [PtCl2(NH3)(L)], where L=5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp) and 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp). Significant 15N NMR upfield shifts (92-95 ppm) were observed for N(3) atom indicating this nitrogen atom as a coordination site. The molecular structure suggest that Pt(II) ion has the square planar geometry with N(3) bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines, N-bonded second ligand (NH3 for cis-[PtCl2(NH3)(L)] or, respectively, 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines for cis-[PtCl2L2]) and two cis chloride anions. The antiproliferative activity in vitro of complexes (1-4) have been tested against the cells of four human cell lines: SW707 rectal adenocarcinoma, A549 non-small cell lung carcinoma, T47D breast cancer and HCV29T bladder cancer. The results indicate a moderate antiproliferative activity of (4) against the cells of rectal, breast and bladder cancer and a marked and selective cytotoxic effect of (1-3) against the cells of all studied human cancer lines.     

CIN85 participates in Cbl-b-mediated down-regulation of receptor tyrosine kinases

The Cbl family of ubiquitin ligases in mammals contains three members, Cbl, Cbl-b, and Cbl-3, that are involved in down-regulation of receptor tyrosine kinases (RTKs) by mediating receptor ubiquitination and degradation. More recently, a novel pathway has been identified whereby Cbl promotes internalization of EGF receptor via a CIN85/endophilin pathway that is functionally separable from the ubiquitin ligase activity of Cbl (1). Here we show that Cbl-b, but not Cbl-3, utilize the same mechanism to down-regulate multiple RTKs. CIN85 was shown to bind to the minimal binding domain identified in the carboxyl terminus of Cbl-b. Ligand-induced phosphorylation of Cbl-b further increased their interactions and led to a rapid and sustained recruitment of CIN85 in the complex with EGF or PDGF receptors. Inhibition of binding between CIN85 and Cbl-b was sufficient to impair Cbl-b-mediated internalization of EGF receptors, while being dispensable for Cbl-b-directed polyubiquitination of EGF receptors. Moreover, CIN85 and Cbl/Cbl-b were constitutively associated with activated PDGF, EGF, or c-Kit receptors in several tumor cell lines. Our data reveal a common pathway utilized by Cbl and Cbl-b that may have an important and redundant function in negative regulation of ligand-activated as well as oncogenically activated RTKs in vivo.     

Clustering-induced signaling of CEACAM1 in PC12 cells

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), an Ig-like transmembrane protein, functions in cell adhesion, angiogenesis and epithelial cell morphogenesis, and has been identified as a tumor suppressor. For all of these functions, CEACAM1 requires signaling capabilities. However, the mechanisms of CEACAM1-mediated signaling are only poorly understood. Here we characterized for the first time CEACAM1 expression and signaling in the neuroendocrine rat pheochromocytoma PC12 cell line. Stimulation of CEACAM1 by ligation on the cell surface with antibodies induced formation of large CEACAM1 clusters and a rapid and transient CEACAM1 tyrosine dephosphorylation. Functionally, this dephosphorylation correlated with a reduced association between CEACAM1 and the tyrosine phosphatase SHP2. Clustering also stimulated binding of CEACAM1 to the actin cytoskeleton, measured by a partial translocation of CEACAM1 into the insoluble fraction after detergent extraction. Both tyrosine dephosphorylation and interaction with the cytoskeleton were sensitive to neuronal differentiation of PC12 cells. The first detected downstream activation of the mitogen-activated protein kinases ERK1 and ERK2, but not of JNK or p38, describes a novel target of CEACAM1-mediated signaling and contributes to the understanding of how CEACAM1 regulates cellular function.     

Changes in the Concentration of Microelements in the Teeth of Rats in the Final Stage of Type 1 Diabetes,with an Absolute Lack of Insulin

The mineral content of tooth hard tissue may influence the rate of decay change. Considering this fact, we aimed at examining if type 1 diabetes might be a contributing factor to the appearance of tooth decay. The experiment was conducted on female Wistar rats. To induce diabetes, rats were intravenously injected with 1 mL streptozocine 0.01 M citrate buffer. The control group of rats was injected with 1 mL 0.01 M citrate buffer only. After 10 days, teeth and blood serum samples were obtained. Fluoride concentration was determined by potentiometer method, and calcium and magnesium, by AAS. Serum concentrations of glucose and estradiol in the diabetic rats were significantly higher compared to the control group. In the experimental group, a statistically significant decrease of fluorine concentration in both teeth and serum were observed. Calcium and magnesium concentrations in blood serum and dental magnesium concentration were significantly higher in rats with type 1 diabetes compared with the control. A downward trend in the content of dental calcium in streptozotocin-induced diabetic rats was observed. The results obtained indicate that caries initiation and progression could be promoted by metabolic changes associated with diabetes affecting the mineral composition of tooth hard tissue.     

Lobular neoplasia found on breast biopsy: marker of increased risk of malignancy or direct pre-cancerous lesion?

The aim of this study was to compare the imaging symptoms and microscopic findings in females with lobular neoplasia (LN) found on biopsy. 1,478 women who underwent primary open biopsy or surgical excision after percutaneous biopsy were reviewed. In 24 of them (1.6%), LN was found. In four patients, excisional biopsy with hook-wire localization was done primarily due to the radial scar. In 20 females, surgical excision of BIRADS 4 lesion was performed because of the presence of LN in specimens from the vacuum-assisted or core-needle percutaneous biopsy. Postoperative pathologic findings were compared to the radiological symptoms. In 13 women, LN did not produce any radiological symptoms and was an additional histologic finding existing near the other lesion: fibroadenoma and radial scar. In none of these lesions was an invasive cancer noticed. In one single patient, ductal carcinoma in situ was observed in the other segment of the breast. Invasive ductal cancer developed in the contralateral breast in one patient. In 11 patients, LN was diagnosed due to radiological symptoms produced by itself. In this group, the invasive lobular cancer was found in seven lesions (64%). Our finding suggests that LN producing suspicious radiological symptoms can be a different biologic type of this lesion when compared asymptomatic LN diagnosed which is usually found on biopsy as additional microscopic pathology. Symptomatic LN is probably associated with a higher potential of malignant transformation.