Case presentation – A five-year survival of the patient with glioblastoma brain tumor

This paper presents an atypical case of a patient with brain tumor of the glioblastoma multiforme (GBM) type who achieved a 5-year survival. Some general information is provided including epidemiology, diagnostic and treatment procedures (surgery and radio-chemo-therapy), and prognosis of survival related to GBM. The course of the disease, including its main symptoms, individual reasons for the delay of adjuvant treatment, after the primary surgical treatment, 37-month period of the decease free survival, as well as comprehensive management after the tumor recurrence are also presented. Histopathology confirming the clinical diagnosis is discussed in a separate chapter.     

Sensory innervation of the dorsal longitudinal ligament and the meninges in the lumbar spine of the dog

Although intervertebral disc herniation is a well-known disease in dogs, pain management for this condition has remained a challenge. The goal of the present study is to address the lack of information regarding the innervation of anatomical structures within the canine vertebral canal. Immunolabeling was performed with antibodies against protein gene product 9.5, Tuj-1 (neuron-specific class III β-tubulin), calcitonin gene-related peptide, and neuropeptide Y in combination with the lectin from Lycopersicon esculentum as a marker for blood vessels. Staining was indicative of both sensory and sympathetic fibers. Innervation density was the highest in lateral areas, intermediate in dorsal areas, and the lowest in ventral areas. In the dorsal longitudinal ligament (DLL), the highest innervation density was observed in the lateral regions. Innervation was lower at mid-vertebral levels than at intervertebral levels. The presence of sensory and sympathetic fibers in the canine dura and DLL suggests that pain may originate from both these structures. Due to these regional differences in sensory innervation patterns, trauma to intervertebral DLL and lateral dura is expected to be particularly painful. The results ought to provide a better basis for the assessment of medicinal and surgical procedures.     

Glycan Dependence of Galectin-3 Self-Association Properties

Human Galectin-3 is found in the nucleus, the cytoplasm and at the cell surface. This lectin is constituted of two domains: an unfolded N-terminal domain and a C-terminal Carbohydrate Recognition Domain (CRD). There are still uncertainties about the relationship between the quaternary structure of Galectin-3 and its carbohydrate binding properties. Two types of self-association have been described for this lectin: a C-type self-association and a N-type self-association. Herein, we have analyzed Galectin-3 oligomerization by Dynamic Light Scattering using both the recombinant CRD and the full length lectin. Our results proved that LNnT induces N-type self-association of full length Galectin-3. Moreover, from Nuclear Magnetic Resonance (NMR) and Surface Plasmon Resonance experiments, we observed no significant specificity or affinity variations for carbohydrates related to the presence of the N-terminal domain of Galectin-3. NMR mapping clearly established that the N-terminal domain interacts with the CRD. We propose that LNnT induces a release of the N-terminal domain resulting in the glycan-dependent self-association of Galectin-3 through N-terminal domain interactions.     

Transmembrane Recognition of the Semaphorin Co-Receptors Neuropilin 1 and Plexin A1: Coarse-Grained Simulations

The cancer associated class 3 semaphorins require direct binding to neuropilins and association to plexins to trigger cell signaling. Here, we address the role of the transmembrane domains of neuropilin 1 and plexin A1 for the dimerization of the two receptors by characterizing the assembly in lipid bilayers using coarse-grained molecular dynamics simulations. From experimental evidence using a two-hybrid system showing the biochemical association of the two receptors transmembrane domains, we performed molecular simulations in DOPC and POPC demonstrating spontaneously assembly to form homodimers and heterodimers with a very high propensity for right-handed packing of the helices. Inversely, left-handed packing was observed with a very low propensity. This mode of packing was observed uniquely when the plexin A1 transmembrane domain was involved in association. Potential of mean force calculations were used to predict a hierarchy of self-association for the monomers: the two neuropilin 1 transmembrane domains strongly associated, neuropilin 1 and plexin A1 transmembrane domains associated less and the two plexin A1 transmembrane domains weakly but significantly associated. We demonstrated that homodimerization and heterodimerization are driven by GxxxG motifs, and that the sequence context modulates the packing mode of the plexin A1 transmembrane domains. This work presents major advances towards our understanding of membrane signaling platforms assembly through membrane domains and provides exquisite information for the design of antagonist drugs defining a novel class of therapeutic agents.     

Evaluation of the Endothelin Receptor Antagonists Ambrisentan,Bosentan, Macitentan,and Sitaxsentan as Hepatobiliary Transporter Inhibitors and Substrates in Sandwich-Cultured Human Hepatocytes

Background

Inhibition of the transporter-mediated hepatobiliary elimination of bile salts is a putative mechanism for liver toxicity observed with some endothelin receptor antagonists (ERAs).

Methods

Sandwich-cultured human hepatocytes were used to study the hepatobiliary distribution and accumulation of exogenous taurocholate, ERAs and endogenous bile acids. The molecular mechanisms for findings in hepatocytes or clinical observations were further explored using either vesicular assays (efflux transporters) or transfected cell-lines (uptake transporters). Inhibition constants (IC₅₀) were measured for the human hepatobiliary transporters bile salt export pump (BSEP), sodium taurocholate cotransporting polypeptide (NTCP), multidrug resistance protein 2 (MRP2), P-glycoprotein (Pgp), breast cancer resistance protein (BCRP), organic anion-transporting polypeptide 1B1 (OATP1B1) and OATP1B3.

Results

The ERAs showed dose-dependent reductions in exogenous taurocholate cellular accumulation in human hepatocytes, with macitentan having the greatest effect. Consistent with their effects on bile acids, the ERAs inhibited bile transporters. IC₅₀ values for OATP1B1 and OATP1B3 ranged from 2 µM for macitentan to 47 µM for ambrisentan. Macitentan and bosentan also inhibited NTCP with IC₅₀ values of 10 and 36 µM, respectively. Similar to previously reported findings with sitaxsentan, BSEP inhibition was observed for bosentan and macitentan with IC₅₀ values of 42 and 12 µM, respectively. In contrast, ambrisentan showed little or no inhibition of these transporters. Other transporters tested were weakly inhibited by the ERAs. Accumulation in hepatocytes was also a factor in the effects on bile transport. Macitentan demonstrated the greatest accumulation in human hepatocytes (∼100x) followed by sitaxsentan (∼40x), bosentan (∼20x) and ambrisentan (∼2x).

Conclusions

Significant differences in the inhibition of hepatic transporters were observed between the evaluated ERAs in vitro. Macitentan had the highest level of cellular accumulation and caused the greatest effects on bile acid distribution in human hepatocytes followed by sitaxsentan and bosentan. Ambrisentan showed a low potential to affect bile acids.     

IL28B Polymorphism Cannot Predict Response to Interferon Alpha Treatment in Patients with Melanoma

Background

Recent genome-wide association studies revealed the rs12979860 single nucleotide polymorphism (SNP) of the IL28B gene (CC genotype) to be the strongest pre-therapeutic predictor of therapy response to interferon alpha in patients with chronic hepatitis C infection. The favorable CC genotype is associated with significantly higher rates of sustained virologic response. No data exist on the role of IL28B polymorphism in interferon therapy of diseases other than viral hepatitis.

Methods

A retrospective study involving 106 patients with melanoma who received low- or high-dose interferon therapy was performed. The CC and non-CC genotype of IL28B rs12979860 SNP were correlated with progression-free and overall survival.

Results

44 (41.5%) patients were CC and 62 (58.5%) non-CC. There was no statistically significant difference in age at diagnosis, melanoma type or localization, Breslow level or AJCC stage between CC and non-CC patients. During the observation period (6.43±4.66 years) disease progression occurred in 36 (34%) patients after 5.5±4.3 years. 43.2% (19) of patients with CC and 27.4% (17) of patients with non-CC genotype were affected (p = 0.091). Disease progression was more frequent in patients on high dose interferon therapy and with a worse AJCC stage.

Conclusion

In contrast to classical risk factors like tumor thickness and clinical stage, IL28B polymorphism was not associated with progression-free or overall survival in patients with melanoma treated with interferon alpha.     

Synthesis of a biotin-tagged photoaffinity probe of 2-azetidinone cholesterol absorption inhibitors

The design and synthesis of a biotin-tagged photoreactive analogue C-4 of the cholesterol absorption inhibitor Ezetimibe is described. Photoaffinity labeling of intestinal brush border membrane vesicles with C-4 and subsequent streptavidin-biotin chromatography leads to selective extraction of a 145 kDa integral membrane protein as the molecular target for cholesterol absorption inhibitors.     

A microprobe study of element distribution in vaginal epithelial cells of the rat

Microprobe analysis of vaginal epithelial cells shed during the estrous cycle of the rat was done to determine cellular elements present in successive stages: pro-estrus, estrus, and post-estrus. Smears of vaginal contents were placed on carbon planchettes, fixed by freeze-drying, and examined in a scanning microscope with an energy dispersive spectrometer. Concentrations of Na, Mg, P, S, Cl, K, and Ca were calculated (mmol/kg dry weight) and analyzed statistically. For phosphorus a significant fall at estrus correlates with a loss of nuclear and cytoplasmic nucleic acids and nucleoproteins. An increase in sulfur at estrus is consistent with an accumulation of keratins over pro-estrus and a greater increase over the post-estrus epithelial cells. The epithelial cells of pro-estrus are highest in Mg and Ca. By post-estrus, the cells have recovered their Mg, not Ca. Potassium concentrations exhibited no significant change between the successive stages.     

Specific Missense Alleles of the Arabidopsis Jasmonic Acid Co-Receptor COI1 Regulate Innate Immune Receptor Accumulation and Function

Plants utilize proteins containing nucleotide binding site (NB) and leucine-rich repeat (LRR) domains as intracellular innate immune receptors to recognize pathogens and initiate defense responses. Since mis-activation of defense responses can lead to tissue damage and even developmental arrest, proper regulation of NB–LRR protein signaling is critical. RAR1, SGT1, and HSP90 act as regulatory chaperones of pre-activation NB–LRR steady-state proteins. We extended our analysis of mutants derived from a rar1 suppressor screen and present two allelic rar1 suppressor (rsp) mutations of Arabidopsis COI1. Like all other coi1 mutations, coi1^rsp missense mutations impair Jasmonic Acid (JA) signaling resulting in JA–insensitivity. However, unlike previously identified coi1 alleles, both coi1^rsp alleles lack a male sterile phenotype. The coi1^rsp mutants express two sets of disease resistance phenotypes. The first, also observed in coi1-1 null allele, includes enhanced basal defense against the virulent bacterial pathogen Pto DC3000 and enhanced effector-triggered immunity (ETI) mediated by the NB–LRR RPM1 protein in both rar1 and wild-type backgrounds. These enhanced disease resistance phenotypes depend on the JA signaling function of COI1. Additionally, the coi1^rsp mutants showed a unique inability to properly regulate RPM1 accumulation and HR, exhibited increased RPM1 levels in rar1, and weakened RPM1-mediated HR in RAR1. Importantly, there was no change in the steady-state levels or HR function of RPM1 in coi1-1. These results suggest that the coi1^rsp proteins regulate NB–LRR protein accumulation independent of JA signaling. Based on the phenotypic similarities and genetic interactions among coi1^rsp, sgt1b, and hsp90.2^rsp mutants, our data suggest that COI1 affects NB–LRR accumulation via two NB–LRR co-chaperones, SGT1b and HSP90. Together, our data demonstrate a role for COI1 in disease resistance independent of JA signaling and provide a molecular link between the JA and NB–LRR signaling pathways.     

Rapid Antigen Processing and Presentation of a Protective and Immunodominant HLA-B*27-restricted Hepatitis C Virus-specific CD8+ T-cell Epitope

HLA-B*27 exerts protective effects in hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. While the immunological and virological features of HLA-B*27-mediated protection are not fully understood, there is growing evidence that the presentation of specific immunodominant HLA-B*27-restricted CD8+ T-cell epitopes contributes to this phenomenon in both infections. Indeed, protection can be linked to single immunodominant CD8+ T-cell epitopes and functional constraints on escape mutations within these epitopes. To better define the immunological mechanisms underlying HLA-B*27-mediated protection in HCV infection, we analyzed the functional avidity, functional profile, antiviral efficacy and naïve precursor frequency of CD8+ T cells targeting the immunodominant HLA-B*27-restricted HCV-specific epitope as well as its antigen processing and presentation. For comparison, HLA-A*02-restricted HCV-specific epitopes were analyzed. The HLA-B*27-restricted CD8+ T-cell epitope was not superior to epitopes restricted by HLA-A*02 when considering the functional avidity, functional profile, antiviral efficacy or naïve precursor frequency. However, the peptide region containing the HLA-B*27-restricted epitope was degraded extremely fast by both the constitutive proteasome and the immunoproteasome. This efficient proteasomal processing that could be blocked by proteasome inhibitors was highly dependent on the hydrophobic regions flanking the epitope and led to rapid and abundant presentation of the epitope on the cell surface of antigen presenting cells. Our data suggest that rapid antigen processing may be a key immunological feature of this protective and immunodominant HLA-B*27-restricted HCV-specific epitope.