Predictive value of the MGMT promoter methylation status in metastatic melanoma patients receiving first-line temozolomide plus bevacizumab in the trial SAKK 50/07

The O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status is a predictive parameter for the response of malignant gliomas to alkylating agents such as temozolomide. First clinical trials with temozolomide plus bevacizumab therapy in metastatic melanoma patients are ongoing, although the predictive value of the MGMT promoter methylation status in this setting remains unclear. We assessed MGMT promoter methylation in formalin-fixed, primary tumor tissue of metastatic melanoma patients treated with first-line temozolomide and bevacizumab from the trial SAKK 50/07 by methylation-specific polymerase chain reaction. In addition, the MGMT expression levels were also analyzed by MGMT immunohistochemistry. Eleven of 42 primary melanomas (26%) revealed a methylated MGMT promoter. Promoter methylation was significantly associated with response rates CR + PR versus SD + PD according to RECIST (response evaluation criteria in solid tumors) (p<0.05) with a trend to prolonged median progression-free survival (8.1 versus 3.4 months, p>0.05). Immunohistochemically different protein expression patterns with heterogeneous and homogeneous nuclear MGMT expression were identified. Negative MGMT expression levels were associated with overall disease stabilization CR+PR+SD versus PD (p=0.05). There was only a poor correlation between MGMT methylation and lack of MGMT expression. A significant proportion of melanomas have a methylated MGMT promoter. The MGMT promoter methylation status may be a promising predictive marker for temozolomide therapy in metastatic melanoma patients. Larger sample sizes may help to validate significant differences in survival type endpoints.

Dendritic glycopeptides as Pseudomonas aeruginosa biofilm inhibitors, Oral presentation, 32nd European Peptide symposium, Athens, Greece, 2-7 September 2012

Glycopeptide dendrimers as Pseudomonas aeruginosa biofilm inhibitors. Glycopeptide dendrimers are being developed for inhibition of pathogen adhesion to host cells, a process mediated by carbohydrate-lectins interactions. Such compounds could be used in the treatment of infections by pathogenic bacteria such as Pseudomonas aeruginosa that can be resistant to known antibiotics. Pseudomonas aeruginosa produces two lectins, the fucose binding LecB and the galactose binding LecA. Both lectins have been shown to be virulence factors, involved in cell adhesion and biofilms formation. Screening combinatorial libraries of fucosylated peptide dendrimers led to the glycopeptide dendrimer (C-Fuc-LysProLeu)4(LysPheLysIle)2 LysHisIleNH2. This dendrimer binds the lectin LecB with submicromolar IC50 and shows potent inhibition of P. aeruginosa biofilms for both the laboratory strain PAO1 and for clinical isolates [1]. Appending the peptide dendrimer portion of FD2 with galactosy endgroups gave galactosylpeptide dendrimers as potent ligands for LecA which also act as biofilm inhibitors. Structure-activity relationship studies demonstrated that multivalency was essential for strong binding and biofilm inhibition. [2]The results open the way to develop therapeutic agents based on glycopeptide dendrimers. Peptide dendrimers with antimicrobial properties and good cell penetration are other applications of dendritic peptides we are now investigating.

Predictors of short term treatment outcome in patients with achalasia following endoscopic or surgical therapy

Pneumatic balloon dilation and surgical myotomy are the most effective treatments for achalasia. While there is controversy which method is best, the aim of the current study was to identify predictors of symptom recurrence after endoscopic or surgical therapy.

Inhibition of the AKT/mTOR and erbB pathways by gefitinib, perifosine and analogs of gonadotropin-releasing hormone I and II to overcome tamoxifen resistance in breast cancer cells

Endocrine resistance in breast cancer remains a major clinical problem and is caused by crosstalk mechanisms of growth factor receptor cascades, such as the erbB and PI3K/AKT pathways. The possibilities a single breast cancer cell has to achieve resistance are manifold. We developed a model of 4-hydroxy-tamoxifen (OHT)‑resistant human breast cancer cell lines and compared their different expression patterns, activation of growth factor receptor pathways and compared cells by genomic hybridization (CGH). We also tested a panel of selective inhibitors of the erbB and AKT/mTOR pathways to overcome OHT resistance. OHT‑resistant MCF-7-TR and T47D-TR cells showed increased expression of HER2 and activation of AKT. T47D-TR cells showed EGFR expression and activated MAPK (ERK-1/2), whereas in resistant MCF-7-TR cells activated AKT was due to loss of CTMP expression. CGH analyses revealed remarkable aberrations in resistant sublines, which were predominantly depletions. Gefitinib inhibited erbB signalling and restored OHT sensitivity in T47D-TR cells. The AKT inhibitor perifosine restored OHT sensitivity in MCF-7-TR cells. All cell lines showed expression of receptors for gonadotropin-releasing hormone (GnRH) I and II, and analogs of GnRH-I/II restored OHT sensitivity in both resistant cell lines by inhibition of erbB and AKT signalling. In conclusion, mechanisms to escape endocrine treatment in breast cancer share similarities in expression profiling but are based on substantially different genetic aberrations. Evaluation of activated mediators of growth factor receptor cascades is helpful to predict response to specific inhibitors. Expression of GnRH-I/II receptors provides multi-targeting treatment strategies.

Problem of Tragedy and Tragic Consciousness in Russia at the turn of the 19th Century

This project intertwines philosophical and historico-literary themes, taking as its starting point the concept of tragic consciousness inherent in the epoch of classicism. The research work makes use of ontological categories in order to describe the underlying principles of the image of the world which was created in philosophical and scientific theories of the 17th century as well as in contemporary drama. Using these categories brought Mr. Vilk to the conclusion that the classical picture of the world implied a certain dualism; not the Manichaean division between light and darkness but the discrimination between nature and absolute being, i.e. God. Mr. Vilk begins with an examination of the philosophical essence of French classical theatre of the XVII and XVIII centuries. The history of French classical tragedy can be divided into three periods: from the mid 17th to early 19th centuries when it triumphed all over France and exerted a powerful influence over almost all European countries; followed by the period of its rejection by the Romantics, who declared classicism to be "artificial and rational"; and finally our own century which has taken a more moderate line. Nevertheless, French classical tragedy has never fully recovered its status. Instead, it is ancient tragedy and the works of Shakespeare that are regarded to be the most adequate embodiment of the tragic. Consequently they still provoke a great number of new interpretations ranging from specialised literary criticism to more philosophical rumination. An important feature of classical tragedy is a system of rules and unities which reveals a hidden ontological structure of the world. The ontological picture of the dramatic world can be described in categories worked out by medieval philosophy - being, essence and existence. The first category is to be understood as a tendency toward permanency and stability (within eternity) connected with this or that fragment of dramatic reality. The second implies a certain set of permanent elements that make up the reality. And the third - existence - should be understood as "an act of being", as a realisation of permanently renewed processes of life. All of these categories can be found in every artistic reality but the accents put on one or another and their interrelations create different ontological perspectives. Mr. Vilk plots the movement of thought, expressed in both philosophical and scientific discourses, away from Aristotle's essential forms, and towards a prioritising of existence, and shows how new forms of literature and drama structured the world according to these evolving requirements. At the same time the world created in classical tragedy fully preserves another ontological paradigm - being - as a fundamental permanence. As far as the tragic hero's motivations are concerned this paradigm is revealed in the dedication of his whole self to some cause, and his oath of fidelity, attitudes which shape his behaviour. It may be the idea of the State, or personal honour, or something borrowed from the emotional sphere, passionate love. Mr. Vilk views the conflicting ambivalence of existence and being, duty as responsibility and duty as fidelity, as underlying the main conflict of classical tragedy of the 17th century. Having plotted the movement of the being/existence duality through its manifestations in 17th century tragedy, Mr. Vilk moves to the 18th century, when tragedy took a philosophical turn. A dualistic view of the world became supplanted by the Enlightenment idea of a natural law, rooted in nature. The main point of tragedy now was to reveal that such conflicts as might take place had an anti-rational nature, that they arose as the result of a kind of superstition caused by social reasons. These themes Mr. Vilk now pursues through Russian dramatists of the 18th and early 19th centuries. He begins with Sumarakov, whose philosophical thought has a religious bias. According to Sumarakov, the dualism of the divineness and naturalness of man is on the one hand an eternal paradox, and on the other, a moral challenge for humans to try to unite the two opposites. His early tragedies are not concerned with social evils or the triumph of natural feelings and human reason, but rather the tragic disharmony in the nature of man and the world. Mr Vilk turns next to the work of Kniazhnin. He is particularly keen to rescue his reputation from the judgements of critics who accuse him of being imitative, and in order to do so, analyses in detail the tragedy "Dido", in which Kniazhnin makes an attempt to revive the image of great heroes and city-founders. Aeneas represents the idea of the "being" of Troy, his destiny is the re-establishment of the city (the future Rome). The moral aspect behind this idea is faithfulness, he devotes himself to Gods. Dido is also the creator of a city, endowed with "natural powers" and abilities, but her creation is lacking internal stability grounded in "being". The unity of the two motives is only achieved through Dido's sacrifice of herself and her city to Aeneus. Mr Vilk's next subject is Kheraskov, whose peculiarity lies in the influence of free-mason mysticism on his work. This section deals with one of the most important philosophical assumptions contained in contemporary free-mason literature of the time - the idea of the trinitarian hierarchy inherent in man and the world: body - soul - spirit, and nature - law - grace. Finally, Mr. Vilk assess the work of Ozerov, the last major Russian tragedian. The tragedies which earned him fame, "Oedipus in Athens", "Fingal" and "Dmitri Donskoi", present a compromise between the Enlightenment's emphasis on harmony and ontological tragic conflict. But it is in "Polixene" that a real meeting of the Russian tradition with the age-old history of the genre takes place. The male and female characters of "Polixene" distinctly express the elements of "being" and "existence". Each of the participants of the conflict possesses some dominant characteristic personifying a certain indispensable part of the moral world, a certain "virtue". But their independent efforts are unable to overcome the ontological gap separating them. The end of the tragedy - Polixene's sacrificial self-immolation - paradoxically combines the glorification of each party involved in the conflict, and their condemnation. The final part of Mr. Vilk's research deals with the influence of "Polixene" upon subsequent dramatic art. In this respect Katenin's "Andromacha", inspired by "Polixene", is important to mention. In "Andromacha" a decisive divergence from the principles of the philosophical tragedy of Russian classicism and the ontology of classicism occurs: a new character appears as an independent personality, directed by his private interest. It was Katenin who was to become the intermediary between Pushkin and classical tragedy.

Expression of FGFRL1, a novel fibroblast growth factor receptor, during embryonic development

FGFRL1 is a novel member of the fibroblast growth factor receptor (FGFR) family. To investigate its expression during mammalian embryonic development, we have used the mouse system. Expression of Fgfrl1 is very low in mouse embryos of day 6 but steadily increases until birth. As demonstrated by in situ hybridization of 16-day-old embryos, the Fgfrl1 mRNA occurs in cartilaginous structures such as the primordia of bones and the permanent cartilage of the trachea, the ribs and the nose. In addition, some muscle types, including the muscles of the tongue and the diaphragm, express Fgfrl1 at relatively high level. In contrast, the heart and the skeletal muscles of the limbs, as well as many other organs (brain, lung, liver, kidney, gut) express Fgfrl1 only at basal level. It is conceivable that Fgfrl1 interacts with other Fgfrs, which are expressed in cartilage and muscle, to modulate FGF signaling.

Expression of phosphoproteins and amelotin in teeth

The organic material of our teeth consists of collagens and a number of calcium-binding phosphoproteins. Six of these phosphoproteins have recently been grouped in the family of the SIBLINGs (small integrin-binding ligand, N-linked glycoproteins), namely osteopontin, bone sialoprotein, dentin matrix protein (DMP1), dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE) and enamelin. We prepared a cDNA library from rat incisors in order to identify the genes involved in tooth formation. The library was screened by subtractive hybridization with two probes; one specific for teeth, the other for bone. We found that the vast majority of the clones from our library were expressed at similar levels in bone and teeth, demonstrating the close relationship of the two tissues. Only 7% of all the clones were expressed in a tooth-specific fashion. These included clones for the enamel proteins; amelotin, amelogenin, ameloblastin and enamelin; for the dentin proteins DSPP and DMP1; and for the intermediate filament protein cytokeratin 13. Several typical bone proteins, including collagen I, osteocalcin, alkaline phosphatase and FATSO, were also expressed at significantly higher levels in teeth than in bone, probably due to the extreme growth rate of rat incisors. The amino acid sequence of rat amelotin showed 62% identity with the sequence from humans. It was expressed considerably later than the other enamel proteins, suggesting that amelotin may serve a function different from those of amelogenin, ameloblastin and enamelin.

An investigation of computer literacy and attitudes amongst Greek post-graduate dental students

An accurate assessment of the computer skills of students is a pre-requisite for the success of any e-learning interventions. The aim of the present study was to assess objectively the computer literacy and attitudes in a group of Greek post-graduate students, using a task-oriented questionnaire developed and validated in the University of Malmö, Sweden. 50 post-graduate students in the Athens University School of Dentistry in April 2005 took part in the study. A total competence score of 0-49 was calculated. Socio-demographic characteristics were recorded. Attitudes towards computer use were assessed. Descriptive statistics and linear regression modeling were employed for data analysis. Total competence score was normally distributed (Shapiro-Wilk test: W = 0.99, V = 0.40, P = 0.97) and ranged from 5 to 42.5, with a mean of 22.6 (+/-8.4). Multivariate analysis revealed 'gender', 'e-mail ownership' and 'enrollment in non-clinical programs' as significant predictors of computer literacy. Conclusively, computer literacy of Greek post-graduate dental students was increased amongst males, students in non-clinical programs and those with more positive attitudes towards the implementation of computer assisted learning.

Increased invasive potential and up-regulation of MMP-2 in MDA-MB-231 breast cancer cells expressing the beta3 integrin subunit

Integrins are a family of transmembrane adhesion receptors that might transduce signals from the extracellular matrix into the inside of cells after ligand binding. In order to investigate whether beta3 integrins expressed in tumor cells might mediate such outside-in signaling, human MDA-MB-231 breast cancer cells that were stably transfected with either beta3 integrin or mock-transfected were investigated in a matrigel degradation assay and a grafting experiment was performed on the developing chicken chorioallantoic membrane (CAM). After cultivation on matrigel for time periods between one and five days, more matrigel was digested in the wells in which beta3 integrin expressing cells were incubated than in wells of mock-transfected cells. Furthermore, extracts of beta3 integrin expressing cells contained higher levels of MMP-2 protein as determined by immunoblotting and more MMP-2 associated gelatinase activity as detected by zymography than extracts of mock-transfected cells. Matrigel degradation and gelatinase activity as well as MMP-2 expression were elevated when beta3 integrin expressing cells were incubated in the presence of the RGD peptide (mimicking an integrin ligand). After grafting on 10 day-old embryonic chicken CAM for three to five days, beta3 integrin expressing cells assembled in spheroids showed higher rates of spreading on the CAM surface and CAM invasion as well as a significant MMP-2 up-regulation compared to mock-transfected cells. The results from the in vivo and in vitro experiments allow the conclusion that the presence of beta3 integrin in MDA-MB-231 breast cancer cells induced an increased MMP-2 expression and activity that might contribute to the enhanced invasive potential observed.