Cell therapy using encapsulated cells producing endostatin

Despite aggressive surgery and post-operative radiation and chemotherapy, the prognosis is poor for glioblastoma patients. Anti-angiogenic therapy with compounds such as endostatin could delay the onset of relapse. However, the short systemic half-life of this proteins as well as the blood-brain barrier makes the use of this therapy difficult for brain cancer patients. The aim of this project is to develop and implant genetically engineered producer cells secreting endostatin that are encapsulated in calcium cross-linked alginate gel beads. Encapsulation of cells within alginate gels has a potential as a sustained release system in addition to the fact that the encapsulation technology protects the cells from rejection by the immune system. Human embryonal kidney 293 cells have been transfected with the gene for endostatin. These cells have been encapsulated in calcium cross-linked alginate gels and optimized for the secretion of endostatin. Alginate gel beads implanted into rat brain have shown only a moderate loss in cell viability but extended endostatin release for periods of up to 12 months. Visualization of the anti-angiogenic effect on C6 rat glioma growth, tumor vasculature and microhemodynamics has been demonstrated by using intravital video microscopy. The data indicates that endostatin greatly affects tumor-associated microcirculation but does not appear to affect normal microcirculation. The local delivery of endostatin seems to specifically affect tumor-associated microvessels by reduction of the vessel density, diameter and functionality. Tumor cell migration and invasion was greatly reduced in the endostatin treated animal

The interaction of platinum-based drugs with native biologically relevant proteins

<p>This study focuses on the identification of the products that are formed upon binding of therapeutically relevant platinum complexes to proteins like beta-lactoglobulin A (LGA), human serum albumin (HSA), or human hemoglobin (HB). The respective proteins were incubated with the platinum-based anticancer drugs cisplatin, carboplatin, and oxaliplatin. LGA was selected as the model protein in addition to the two most abundant blood proteins HSA and HB. In case of the model protein, the effect of free thiol groups on the affinity of cisplatin, carboplatin, and oxaliplatin was investigated by means of liquid chromatography electrospray ionization time-of-flight mass spectrometry (LC/ESI-ToF-MS). The reduced form of LGA, which contains four free thiol groups more than the native LGA, shows a much higher affinity to the platinum-based drugs. By means of liquid chromatography coupled to inductively coupled plasma mass spectrometry, the reaction behavior of the platinum-based drugs towards HSA and HB was investigated under different conditions considering the chloride concentration (4 or 100 mM) and the incubation time (24 and 48 h). In case of carboplatin, less than 6 % protein-bound platinum was detected. However, both cisplatin and oxaliplatin display a high affinity to the proteins investigated. Further information was obtained by means of LC/ESI-ToF-MS. In case of oxaliplatin, the complex [Pt(DACH)](2+) (DACH = C6N2H14) was identified interacting with HSA and HB. For cisplatin, different results were observed for the two proteins. The complex [Pt(NH3)(2)Cl](+) interacted predominantly with HSA and [Pt(NH3)(2)](2+) with HB.</p>