4E-binding protein 1, a cell signaling hallmark in breast cancer that correlates with pathologic grade and prognosis.

PURPOSE: Cell signaling pathways include a complex myriad of interconnected factors from the membrane to the nucleus, such as erbB family receptors and the phosphoinositide-3-kinase/Akt/mTOR and Ras-Raf-ERK cascades, which drive proliferative signals, promote survival, and regulate protein synthesis. EXPERIMENTAL DESIGN: To find pivotal factors in these pathways, which provide prognostic information in malignancies, we studied 103 human breast tumors with an immunohistochemical profile, including total and phosphorylated (p) proteins: human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor, extracellular signal-regulated kinase 1/2, Akt, 4E-binding protein 1 (4EBP1), eukaryotic initiation factor 4E, phosphorylated ribosomal protein S6 kinase 1, phosphorylated ribosomal protein S6, and Ki67. Western blot and reverse lysate protein arrays were also done in a subset of tumors. RESULTS: Significantly, activation of the phosphoinositide-3-kinase/Akt/mTOR cascade was detected in a high proportion of tumors (41.9%). Tumors with HER2 overexpression showed higher p-Akt as compared with negative tumors (P < 0.001). Levels of p-Akt correlated with the downstream molecules, p-4EBP1 (P = 0.001) and p-p70S6K (P = 0.05). Although 81.5% of tumors expressed p-4EBP1, in 16.3% of these tumors, concomitant activation of the upstream factors was not detected. Interestingly, p-4EBP1 was mainly expressed in poorly differentiated tumors (P < 0.001) and correlated with tumor size (P < 0.001), presence of lymph node metastasis (P = 0.002), and locoregional recurrences (P = 0.002). Coexpression of p-4EBP1 and p-eIF4G correlated with a high tumor proliferation rate (P = 0.012). CONCLUSION: In this study, p-4EBP1 was the main factor in signaling pathways that associate with prognosis and grade of malignancy in breast tumors. Moreover, p-4EBP1 was detected in both HER2-positive and HER2-negative tumors. This factor seems to be a channeling point at which different upstream oncogenic alterations converge and transmit their proliferative signal, modulating protein translation.     

Characterization of an O-glycosylated plaque-associated protein from Alzheimer disease brain

In this work we characterized a 90-kDa glycoprotein from Alzheimer disease (9OAzgp) brain extracts that is recognized by the GalNAc-specific lectin from Amaranthus leucocarpus (ALL), as determined through Western blot. The 90Azgp was purified by electro-elution, and its amino acid sequence determined from peptides obtained after trypsin digestion through MALDI-TOF (Matrix-assisted laser desorption ionization-time of flight), and compared with the relative values obtained from the NCBInr (Swiss-Prot 10/01/2001) database. The 90Azgp showed 32% and 42% homology with the KIAA0310 protein from human brain and the human gastric mucin, respectively. Presence of O-glycosidically linked glycans in the proteins recognized by ALL was confirmed by inhibition of the lectin-glycoprotein interaction through hapten-inhibition assays and also by elimination of the O-glycosidically linked glycans after treatment with O-glycanase from Diplococcus pneumoniae. Electron transmission microscopy confirmed that the receptor recognized by the lectin is processed in the Golgi apparatus of AD neurons. Although the specific role of this glycoprotein has not been identified, considering that the presence of this lectin receptor co-localized with neuritic plaques and in AD sprouting neurons, it could suggest that the O-glycosyl-protein identified by the A. leucocarpus lectin participates in the pathogenesis of neurodegenerative diseases.     

Orthomolecular oncology: a mechanistic view of intravenous ascorbate's chemotherapeutic activity

The effect of vitamin C in cancer has been a subject of great controversy; mainly because of the inconsistent results obtained by oral intakes of ascorbate when used as an anticancer agent. We believe the intravenous application of ascorbate will provide more consistent results in cancer patients since Vitamin C blood levels attained are substantially higher in a range proven cytotoxic to malignant cells. In this article we will present and discuss our proposed mechanism on the chemotherapeutic activity exhibited by ascorbate.     

A man with lung cancer and tuberculosis: a false positive by positron emission tomography and its clinical repercussions

Positron emission tomography (PET) has come to play an increasingly important role in the evaluation of lung cancer patients, both for diagnostic staging and post-treatment follow-up. As is true for other techniques, PET gives false positive and negative results. False positives have been described in the presence of certain active infections and inflammatory lesions, such as tuberculous granulomas, coccidioidomycosis, aspergillosis and histoplasmosis. We report the case of a man whose PET gave a false positive and in whom both lung cancer and tuberculosis were present. A radical change in therapeutic approach was required, making the case interesting.     

Dependency of cyclosporine tissue distribution and metabolism on the age and gender of rats after a single intravenous dose

In a previous study we demonstrated the dependency of cyclosporine (CyA) pharmacokinetics on the age and gender of Wistar rats given 10 mg/kg intravenously. The present study has been conducted under the same experimental conditions (10 mg/kg as a single intravenous dose) to identify the mechanisms behind such differences. On the one hand, drug distribution was studied by measuring the CyA levels in blood, liver, kidney, spleen, adipose tissue, skin and muscle at 48 h post-treatment by using a specific fluorescence polarization immunoassay (m-FPIA, Abbott Laboratories). Drug blood and tissue levels in male rats were significantly higher than the female counterparts except for adipose tissue where the concentrations were 2-fold higher in females. In males, the highest CyA concentrations were observed in the liver, followed in rank order by kidney and spleen, fat, skin, muscle, then blood. On the contrary, females showed the highest drug levels in fat, followed by liver, kidney, spleen, skin, muscle and blood. Age exerted a significant influence on CyA tissue levels in males but no effect was observed in females. The potential differences in drug metabolism were established by measuring (HPLC) the amounts of CyA and its metabolites accumulated in faeces after hepatic biotransformation and biliary excretion. The amounts of circulating metabolites in blood as well as those accumulated and excreted in the liver and urine were also estimated by using specific (m-FPIA) and non-specific fluorescence polarization immunoassay (p-FPIA, Abbott Laboratories), respectively. The analysis of faeces revealed that AM9 was the major identified metabolite with females excreting lower amounts of unchanged CyA than males. In addition, the comparison of the AUC values corresponding to parent CyA and total CyA derivatives suggested that blood concentrations of CyA metabolites were higher in females indicating higher biotransformation rates. Therefore, both CyA distribution and metabolism are responsible for the sex-associated differences in drug pharmacokinetics previously found in rats.     

Salmonella vaccine carrier strains: effective delivery system to trigger anti-tumor immunity by oral route

Recombinant Salmonella strains expressing heterologous antigens can be delivered by oral route triggering the elicitation of efficient antigen-specific humoral, T helper and cytotoxic responses. The potential of attenuated Salmonella spp. to trigger anti-tumor immunity was evaluated for the first time by using beta-galactosidase (beta-gal) as a model tumor-associated antigen (TAA). Beta-gal was expressed in a Salmonella typhimurium aroA vaccine carrier strain either constitutively or under the control of a promoter activated upon infection. Oral immunization with both vaccine prototypes resulted in the elicitation of beta-gal-specific humoral and cell-mediated immunity. Although both strains were able to trigger antigen-specific CTL, responses were more efficient when the expression was controlled by the promoter activated upon infection. The anti-tumor efficacy of the stimulated response was validated by challenging vaccinated animals with an aggressive fibrosarcoma transfected with beta-gal, which operationally acts as a TAA. Both groups of vaccinated mice exhibited a significant reduction in tumor take and growth with respect to animals vaccinated with plasmidless carrier (p < 0.05). However, the overall efficiency was better in the group in which beta-gal was controlled by the in vivo-activated promoter (85% versus 54%; p < 0.05).