Biomedical subjects

Dominik Krilleke

Publications and source records attributed to Dominik Krilleke.

3 recordsLinked to original sources

PubMed2005

A therapeutic aptamer inhibits angiogenesis by specifically targeting the heparin binding domain of VEGF165.

Aptamers recognize their targets with extraordinary affinity and specificity. The aptamer-based therapeutic, Macugen, is derived from a modified 2'fluoro pyrimidine RNA inhibitor to vascular endothelial growth factor (VEGF) and is now being used to treat the wet form of age-related macular degeneration. This VEGF(165) aptamer binds specifically to the VEGF(165) isoform, a dimeric protein with a receptor-binding domain and a heparin-binding domain (HBD). To understand the molecular recognition between VEGF and this aptamer, binding experiments were used to show that the HBD contributes the majority of binding energy in the VEGF(165)-aptamer complex. A tissue culture-based competition assay demonstrated that the HBD effectively competes with VEGF(165) for aptamer binding in vivo. Comparison of NMR spectra revealed that structural features of the smaller HBD-aptamer complex are present in the full-length VEGF(164)-aptamer complex. These data show that the HBD provides the binding site for the aptamer and is the primary determinant for the affinity and specificity in the VEGF(165)-aptamer complex.

Aptamers, Nucleotide↗

PubMed2005

VEGF function in vascular pathogenesis.

Vascular endothelial growth factor (VEGF) has proven to be the most critical angiogenic factor identified to date; its discovery has transformed the field of angiogenesis research. After two decades of intense studies by numerous laboratories, the complex biology of VEGF is slowly being elucidated. VEGF is a collection of several different isoforms with overlapping but also unique functions. Furthermore, there are at least four different VEGF receptors, adding to the complexity of the VEGF/receptor system. VEGF exerts its effects on endothelial cells, inflammatory cells and neuronal cells, and its expression may contribute to the pathologies of diseases ranging from retinopathies to cancer. This review focuses on the biochemistry and cell biology of VEGF, with particular emphasis on the different isoforms and receptors, thereby illustrating the multifunctional nature of this growth factor. Lastly, critical considerations based on the complex biology of VEGF for developing specific and more targeted anti-VEGF therapeutic agents will be discussed.

Angiogenesis Inhibitors↗

PubMed2003

Inhibition of JNK signaling diminishes early but not late cellular stress-induced apoptosis.

The human leukemic T-cell line Jurkat was used to define the role of the cellular stress pathway with its key player kinase JNK in cancer therapy-induced apoptosis. JNK activity was inhibited by stable transfection with a dominant negative mutant of the upstream kinase JNKK/MKK4 or with the novel, potent and selective JNK1, -2 and -3 inhibitor SP600125. Inhibition of JNK activity delayed the onset of apoptosis induced by cisplatin, doxorubicin, gamma-irradiation and CD95-L but did not prevent apoptosis per se. Early events during apoptosis such as induction of CD95-L, activation of caspase-8 and exposure of phosphatidylserine on the cell surface were strongly inhibited. Also, at early time points of apoptosis, loss of the mitochondrial membrane potential and release of cytochrome c were markedly impaired. However, late signaling events during apoptosis such as cleavage of PARP and DNA fragmentation apoptosis were only marginally affected. These findings are in accordance with the activity of initiator and effector caspases. Whereas activity of the initiator caspase-8 was strongly inhibited early and late after induction, an inhibition of caspase-3 activity was only observed early after induction of apoptosis. We therefore suggest that cellular stress signaling contributes to the initiation of apoptosis, whereas it might be dispensable for the progression of apoptosis. Dysfunction of this pathway under pathological conditions might contribute to therapy resistance of cancer cells.

Anthracenes↗