Recurrent glioblastoma multiforme (GBM), insensitive against most therapeutic interventions, has low response and survival rates. Temozolomide (TMZ) was approved for second-line therapy of recurrent anaplastic astrocytoma. However, TMZ therapy in GBM patients reveals properties such as reduced tolerability and inauspicious hemogram. The solution addressed here concerning GBM therapy consolidates and uses the potential of organic and peptide chemistry with molecular medicine. We enhanced the pharmacologic potency with simultaneous reduction of unwanted adverse reactions of the highly efficient chemotherapeutic TMZ. The TMZ connection to transporter molecules (TMZ-BioShuttle) was investigated, resulting in a much higher pharmacological effect in glioma cell lines and also with reduced dose rate. From this result we can conclude that a suitable chemistry could realize the ligation of pharmacologically active, but sensitive and highly unstable pharmaceutical ingredients without functional deprivation. The TMZ-BioShuttle dramatically enhanced the potential of TMZ for the treatment of brain tumors and is an attractive drug for combination chemotherapy.

There is a large number of effective cytotoxic drugs whose side effect profile, efficacy, and long-term use in man are well understood and documented over decades of use in clinical routine e.g. in the treatment of recurrent glioblastoma multiforme (GBM) and the hormone-refractory prostate cancer (HRPC). Both cancers are insensitive against most chemotherapeutic interventions; they have low response rates and poor prognoses. Some cytotoxic agents can be significantly improved by using modern technology of drug delivery or formulation. We succeeded to enhance the pharmacologic potency with simultaneous reduction of unwanted adverse reactions of the highly efficient chemotherapeutic temozolomide (TMZ) as an example. The TMZ connection to transporter molecules (TMZ-BioShuttle) resulted in a much higher pharmacological effect in glioma cell lines while using reduced doses. This permits the conclusion that a suitable chemistry could realize the ligation of pharmacologically active, but sensitive and highly unstable pharmaceutical ingredients without functional deprivation. The re-formulation of TMZ to TMZ-BioShuttle achieved a nearly 10-fold potential of the established pharmaceutic TMZ far beyond the treatment of brain tumors cells and results in an attractive reformulated drug with enhanced therapeutic index.

The Human immunodeficiency virus 1 derived capsid assembly inhibitor peptide (HIV-1 CAI-peptide) is a promising lead candidate for anti-HIV drug development. Its drawback, however, is that it cannot permeate cells directly. Here we report the transport of the pharmacologically active CAI-peptide into human lymphocytes and Human Embryonic Lung cells (HEL) using the BioShuttle platform. Generally, the transfer of pharmacologically active substances across membranes, demonstrated by confocal laser scanning microscopy (CLSM), could lead to a loss of function by changing the molecule's structure. Molecular dynamics (MD) simulations and circular dichroism (CD) studies suggest that the CAI-peptide has an intrinsic capacity to form a helical structure, which seems to be critical for the pharmacological effect as revealed by intensive docking calculations and comparison with control peptides. This coupling of the CAI-peptide to a BioShuttle-molecule additionally improved its solubility. Under the conditions described, the HIV-1 CAI peptide was transported into living cells and could be localized in the vicinity of the mitochondria.

Bei physiologischen Prozessen wie der Embryo- und Organogenese und in der Pathologie–etwa der Invasion und Metastasierung von Karzinomen–spielen klassische Cadherine, homophile Transmembran-Glykoproteine von Adhaerens-Zell-Verbindungen, anerkanntermaßen eine bedeutende Rolle. Im letzten Jahrzehnt erschienen darüber hinaus zahlreiche Artikel, die eine Reduktion der E-Cadherin-Synthese, des typischen epithelialen Cadherins, und eine Zunahme des N-Cadherins, des klassischen neuralen bzw. mesenchymalen Cadherins, mit dem Invasionsverhalten und dem Metastasierungspotential verschiedener Karzinome, auch des hepatozellulären Karzinoms, korrelierten und als diagnostisches Kriterium in die Literatur eingeführt haben.

Substrate-adherent cultured cells derived from human bone marrow or umbilical cord blood ("mesenchymal stem cells") are of special interest for regenerative medicine. We report that such cells, which can display considerable heterogeneity with respect to their cytoskeletal protein complement, are often interconnected by special tentacle-like cell processes contacting one or several other cells. These processus adhaerentes, studded with many (usually small) puncta adhaerentia and varying greatly in length (up to more than 400 microm long), either contact each other in the intercellular space ("ET touches") or insert in a tight-fitting manner into deep plasma membrane invaginations (recessus adhaerentes), thus forming a novel kind of long (up to 50 microm) continuous cuff-like junction (manubria adhaerentia). The cell processes contain an actin microfilament core that is stabilized with ezrin, alpha-actinin, and myosin and accompanied by microtubules, and their adhering junctions are characterized by a molecular complement comprising the transmembrane glycoproteins N-cadherin and cadherin-11, in combination with the cytoplasmic plaque proteins alpha- and beta-catenin, together with p120(ctn), plakoglobin, and afadin. The processes are also highly dynamic and rapidly foreshorten as cell colonies approach a denser state of cell packing. These structures are obviously able to establish cell-cell connections, even over long distances, and can form deep-rooted and tight cell-cell adhesions. The possible relationship to similar cell processes in the embryonic primary mesenchyme and their potential in cell sorting and tissue formation processes in the body are discussed.

An efficient gene transfer into target tissues and cells is needed for safe and effective treatment of genetic diseases like cancer. In this paper, we describe the development of a transport system and show its ability for transporting plasmids. This non-viral peptide-based BioShuttle-mediated transfer system consists of a nuclear localization address sequence realizing the delivery of the plasmid phNIS-IRES-EGFP coding for two independent reporter genes into nuclei of HeLa cells. The quantification of the transfer efficiency was achieved by measurements of the sodium iodide symporter activity. EGFP gene expression was measured with Confocal Laser Scanning Microscopy and quantified with biostatistical methods by analysis of the frequency of the amplitude distribution in the CLSM images. The results demonstrate that the “BioShuttle”-Technology is an appropriate tool for an effective transfer of genetic material carried by a plasmid.

The actin-binding protein (ABP) drebrin, isoform E2, is involved in remodelling of the actin cytoskeleton and in formation of cell processes, but its role in cell migration has not yet been investigated. Therefore, we have studied the organization of drebrin in motile cultured cells such as murine B16F1 melanoma and human SV80 fibroblast cells, using live cell confocal microscopy. In cells overexpressing DNA constructs encoding drebrin linked to EGFP, numerous long, branched cell processes were formed which slowly retracted and extended, whereas forward movement was halted. In contrast, stably transfected B16F1 cells containing drebrin-EGFP at physiological levels displayed lamellipodia and were able to migrate on laminin. Surprisingly, in such cells, drebrin was absent from anterior lamellipodia but was enriched in a specific juxtanuclear zone, the "drebrin-enriched zone" (DZ), and in the tail. In leading edges of SV80 cells, characterized by pronounced actin microspikes, drebrin was specifically enriched along posterior portions of the microspikes, together with tropomyosin. Drebrin knock-down by small interfering RNAs did not impair movements of SV80 cells. Our results confirm the role of drebrin E2 in the formation of branching processes and further indicate that during cell migration, the protein contributes to retraction of the cell body and the tail but not to lamellipodia formation. In particular, the novel, sizable juxtanuclear DZ structure will have to be characterized in future experiments with respect to its molecular assembly and cell biological functions.

Recent studies on the subcellular distribution of cytoplasmic plaque proteins of intercellular junctions have revealed that a number of such proteins can also occur in the cyto- and the nucleoplasm. This occurrence in different, and distant locations suggest that some plaque proteins play roles in cytoplasmic and nuclear processes in addition to their involvement in cell-cell adhesive interactions. Plakophilin (PKP) 3, a member of the arm-repeat family of proteins, occurs, in a diversity of cell types, both as an architectural component in plaques of desmosomes and dispersed in cytoplasmic particles. In immuno-selection experiments using PKP3-specific antibodies, we have identified by mass spectrometric analysis the following RNA-binding proteins: Poly (A) binding protein (PABPC1), fragile-X-related protein (FXR1), and ras-GAP-SH3-binding protein (G3BP). Moreover, the RNA-binding proteins codistributed after sucrose gradient centrifugation in PKP3-containing fractions corresponding to 25-35 S and 45-55 S. When cells are exposed to environmental stress (e.g., heat shock or oxidative stress) proteins FXR1, G3BP, and PABPC1 are found, together with PKP3 or PKP1, in "stress granules" known to accumulate stalled translation initiation complexes. Moreover, the protein eIF-4E and the ribosomal protein S6 are also detected in PKP3 particles. Our results show that cytoplasmic PKP3 is constitutively associated with RNA-binding proteins and indicate an involvement in processes of translation and RNA metabolism.

Goal in pharmaceutical research is achievement of necessary drug concentrations in the target organ, effective treatment with safe delivery of genetic agents, while sparing normal tissue and minimizing side effects. A new “BioShuttle”-delivery system harbouring a cathepsin B cutting site, a nuclear address sequence and a functional peptide was developed and tumor cells were treated. Transport and subcellular activation were determined by confocal laser scanning microscopy permitting the conclusion: BioShuttle-conjugates prove as efficient tools for genetic interventions by selective and topical activation of therapeutic peptide precursors by enzymatic cleavage. As shown here for glioma cells and the cathepsin B cleavable site, living cells can be treated with high specificity and selectivity for diagnostic and therapeutic purposes.

The human small glutamine-rich TPR-containing protein (hSGT) is essential for cell division since RNA-interference-mediated strong reduction of hSGT protein levels causes mitotic arrest (M. Winnefeld, J. Rommelaere, and C. Cziepluch, The human small glutamine-rich TPR-containing protein is required for progress through cell division, Exp. Cell Res. 293 (2004), 43-57). Analysis of HeLa cells expressing a histone 2A-YFP fusion protein revealed the continuous presence of few mislocalized chromosomes close to the spindle poles as possible cause for hSGT depletion-dependent prometaphase arrest. Cells unable to rescue these mislocalized chromosomes into the metaphase plate died at this stage through apoptosis. In order to address hSGT function at the molecular level, mass spectrometry analysis of proteins which co-immunoprecipitated with Flag-tagged hSGT was performed. Thereby, Hsp70 and Bag-6/Bat-3/Scythe were identified as novel hSGT interaction partners while interaction with Hsc70 was confirmed. Results obtained with truncated versions of the hSGT protein revealed that Bag-6/Bat-3/Scythe and Hsp70 or Hsc70 were independently able to form complexes with hSGT. Interaction of hSGT with Hsc70, Hsp70 or Bag-6/Bat-3/Scythe was demonstrated in prometaphase, thereby suggesting a possible role for complexes containing hSGT and distinct (co)-chaperones during mitosis. Finally, cells from populations with reduced levels of Bag-6/Bat-3/Scythe also displayed persistence of mislocalized chromosomes and mitotic arrest, which strongly indicated that hSGT-Bag-6/Bat-3/Scythe complexes could be directly or indirectly required for complete chromosome congression.

Aglaia (family Meliaceae) plants are used in traditional medicine (e.g., in Vietnam) for the treatment of inflammatory skin diseases and allergic inflammatory disorders such as asthma. Inflammatory diseases arise from inappropriate activation of the immune system, leading to abnormal expression of genes encoding inflammatory cytokines and tissue-destructive enzymes. The active compounds isolated from these plants are derivatives of rocaglamide. In this study we show that rocaglamides are potent immunosuppressive phytochemicals that suppress IFN-gamma, TNF-alpha, IL-2, and IL-4 production in peripheral blood T cells at nanomolar concentrations. We demonstrate that rocaglamides inhibit cytokine gene expression at the transcriptional level. At the doses that inhibit cytokine production, they selectively block NF-AT activity without impairing NF-kappaB and AP-1. We also show that inhibition of NF-AT activation by rocaglamide is mediated by strong activation of JNK and p38 kinases. Our study suggests that rocaglamide derivatives may serve as a new source of NF-AT-specific inhibitors for the treatment of certain inflammatory diseases.

In nontumorigenic mammary epithelial cells (EpH4), transforming growth factor- β (TGF β 1) causes cell cycle arrest/apoptosis, but induces epitheliomesenchymal transition (EMT) in Ha- Ras -transformed EpH4 cells (EpRas). EMT is closely correlated with late-stage tumor progression and results in fibroblastic, migratory cells displaying a mesenchymal gene expression program (FibRas). EpRas and FibRas cells showed strongly increased cell substrate adhesion to fibronectin, collagens I/IV and laminin 1. Furthermore, Ras transformation caused enhanced or de-novo expression of the integrin subunits β 1, α 2 and α 3, or α 5 and α 6, respectively, the latter subunits being even more strongly expressed in FibRas cells. Importantly, polarized EpRas cells expressed integrin subunits β 1 and α 6 at distinct (apical and lateral) membrane domains, while FibRas cells coexpressed these integrins and α 5 at the entire plasma membrane. During EMT, EpRas cells formed an α 5 β 1 complex and deposited its ligand fibronectin into the extracellular matrix. Function-blocking α 5 antibodies attenuated migration, and caused massive apoptosis in EpRas cells undergoing TGF β 1-induced EMT in collagen gels, but failed to affect EpRas- or FibRas-derived structures. We conclude that functional α 5 β 1 integrin is centrally implicated in EMT induction. Importantly, FibRas cells also failed to deposit the α 6 β 4 ligand laminin 5, suggesting that α 6 β 4 is no longer functional after EMT and replaced by mesenchymal integrins such as α 5 β 1.

Isoform E2 of drebrin, an actin-binding protein originally identified in neuronal cells, has recently been identified in diverse non-neuronal cells, mostly in association with cell processes and intercellular junctions. Here, we report on the presence of drebrin in normal human skin, epithelial skin cancers, and cultured keratinocytes. Keratinocytes of normal epidermis contain almost no drebrin but the protein is readily seen in hair follicles. By immunohistochemistry and immunoblot, basal cell carcinomas (BCC) are rich in drebrin, and confocal laser scanning and immunoelectron microscopy show accumulation at adhering junctions, in co-localization with actin and partially with plaque proteins. In squamous cell carcinomas, keratoacanthomas, and in epidermal precancers, drebrin is heterogeneously distributed, appearing as mosaics. Primary keratinocyte cultures contain significant amounts of drebrin enriched at adhering junctions. When epithelium-derived cells devoid of drebrin are transfected with drebrin-enhanced green fluorescent protein, constructs accumulate in the cell periphery, and immunoprecipitation shows complexes with actin. During epidermal growth factor induced formation of cell processes, drebrin retains this junction association, as observed by live cell microscopy. Our results suggest novel functions of drebrin such as an involvement in cell-cell adhesion and tumorigenesis and a potential value in diagnosis of BCC.