Gemcitabine Maintenance Therapy in Patients With Metastasized Soft Tissue Sarcomas

Background: Metastasized soft-tissue sarcomas still pose a significant therapeutic challenge given the limited efficacy of currently available multimodal treatment strategies. Recent progress in molecular characterization of sarcoma subtypes has enabled successful personalized therapy approaches in a minority of selected patients with targetable mutations. However, in the majority of patients with refractory soft tissue sarcomas, long-term survival remains poor. Methods: We report on three adult patients with various soft tissue sarcomas subjected to Gemcitabine maintenance therapy. Tumor entities included leiomyosarcoma of the pancreas (patient 1), undifferentiated pleomorphic sarcoma of the right femur (patient 2), and peri-aortic leiomyosarcoma (patient 3). Metastatic sites encompassed liver, lung, and bones. All patients received Gemcitabine maintenance therapy until disease progression following prior salvage chemotherapy with Docetaxel and Gemcitabine. Patients were treated outside of clinical trials. Response assessment was based on radiological imaging. Results: In response to salvage chemotherapy with Docetaxel and Gemcitabine, one patient exhibited a partial remission, and two patients showed stable disease. Patient 1 exhibited stable disease for 6 months during Gemcitabine maintenance therapy before suffering rapid progression of hepatic metastases. Patient 2 underwent 21 months of Gemcitabine maintenance therapy, which was discontinued after progressive pulmonary metastases were detected. Patient 3 is still being treated with Gemcitabine maintenance therapy. Remarkably, owing to significant chemotherapy-associated hematotoxicity, the dose of Gemcitabine dose was reduced by two-thirds. Nevertheless, stable disease with constant pulmonary metastases has been maintained in this patient for 14 months. Conclusions: Gemcitabine maintenance therapy following prior Docetaxel and Gemcitabine chemotherapy is manageable and reveals potential benefits for patients with aggressive metastasized soft tissue sarcomas. Prospective trials evaluating Gemcitabine maintenance therapy are encouraged

Pharmacology and quantitative structure-activity relationships of imidazolylpropylguanidines with mepyramine-like substructures as non-peptide neuropeptide Y Y_1 receptor antagonists,

The design of non-peptide, Y1-selective antagonists of neuropeptide Y (NPY) as pharmacological tools is in progress and is increasingly important as therapeutic applications are expected. Starting from the potent histamine H2 agonist and weak NPY Y1 antagonist arpromidine, 16 imidazolylpropylguanidine derivatives were synthesized and tested for Y1 antagonistic activity (inhibition of NPY-stimulated Ca2+ increase in human erythroleukemic cells), where the pheniramine-like moiety of arpromidine was replaced with 2-pyridylaminoalkyl, benzyl-(2-pyridyl)aminoalkyl, and phenyl-(2-pyridyl)alkylaminoalkyl partial structures derived from mepyramine. The pA2 values of the most active compounds are in the range of 6.2-6.5. Quantitative structure-activity relationships (QSAR) were investigated by fragment regression analysis. Results indicate that a tetramethylene spacer between the guanidino group and the amino nitrogen is optimal. For an at least moderate degree of Y1 antagonistic activity, a second benzyl or phenyl group must be present in addition to the 2-pyridyl ring. At this second group, hydrophobic substituents such as 3,4-di-CI and 4-Br further enhance Y1 antagonism. The most active derivative additionally bears a 5-Br substituent at the 2-pyridyl moiety. Structure-activity relationships suggest that the compounds might be able to partially imitate the role of NPY when interacting with Y1 receptors and thus behave as moderate non-peptide NPY Y1 antagonist

Hepatocellular carcinoma cells surviving doxorubicin treatment exhibit increased migratory potential and resistance to doxorubicin re-treatment in�vitro

Transarterial chemoembolization (TACE) is an established therapeutic approach for the treatment of hepatocellular carcinoma (HCC). Although patients who undergo TACE may have prolonged survival, there are indications that the malignancy of residual HCC tissue can increase subsequent to the procedure. Although hypoxia, which occurs during TACE due to ischemia, is known to contribute to angiogenesis, little is known with regard to the undesirable effects of chemotherapeutic agents on residual HCC cells. Doxorubicin is one of the most commonly used drugs in TACE. The aim of the present study was to analyze alterations in Hep3B and HepG2 human HCC cell lines surviving doxorubicin treatment in vitro. Initially, the toxic concentration range was determined, and doxorubicin was subsequently applied in concentrations that killed >80% of the HCC cells. During the first days subsequent to treatment, surviving cells had higher expression levels of the epithelial-mesenchymal transition marker SNAIL, and exhibited increased migratory activity compared with control cells. At 3 weeks after the first doxorubicin treatment, surviving HCC cells tolerated significantly higher doxorubicin concentrations compared with control cells. As a potential explanation for this doxorubicin resistance, significantly increased mRNA expression levels of ATP-binding cassette ABCB1 (multidrug resistance protein 1) and ABCC1 (multidrug resistance-associated protein 1) were observed by reverse transcription-quantitative polymerase chain reaction. In summary, these findings indicate that, following TACE treatment, hypoxia as well as doxorubicin may induce a more malignant phenotype in surviving HCC cells and decrease susceptibility to further chemotherapeutic treatment

Label-free analysis of GPCR-stimulation: The critical impact of cell adhesion

Label-free cell-based assays have been attracting growing attention in drug research. Optical approaches based on evanescent electric fields (e.g. EPIC, RWG/DMR, SPR) and electrochemical impedance analysis (ECIS, xCELLigence) are by far the most widespread techniques for such purposes. We compared three label-free approaches (ECIS, RWG/DMR and SPR) with respect to the activation of the human histamine H-1 receptor (H1R) expressed by U-373 MG glioblastoma and genetically engineered HEK 293T cells. HEK 293T cells were either expressing the hH(1)R alone or in combination with the adhesion protein hMSR1. The beta(2)-adrenergic receptor (beta(2)-AR) expressed by bovine aortic endothelial cells (BAEC) served as a second cell model. Reduced cell adhesion to the surface of the sensing devices affected both, the optical and the impedance-based readout, but became much more obvious in case of RWG- or SPR-based assays. By contrast, the co-expression of hH(1)R and hMSR1 in HEK 293T cells strongly enhanced the signal compared to hH(1)R expression alone. As the sensitivity of the optical readouts is confined to a distance of 100-200 nm from the surface, depending on the wavelength of the incident light, this observation is in accordance with tighter adhesion of the co-transfectants, inducing a shorter distance between the cell membrane and the substrate. Combining ECIS and SPR, allowing for simultaneous registration of both signals for a single cell population, provided a direct correlation of both readouts, when H1R or (beta(2)-AR stimulation was investigated for the same cell populations. Cell adhesion was found to have a critical impact on the results of label-free cell monitoring, in particular when techniques based on evanescent electric fields are applied. (C) 2016 Published by Elsevier Ltd

Loratadine and analogs: Discovery and preliminary SAR of inhibitors of the amino acid transporter B0AT2

B0AT2, encoded by the SLC6A15 gene, is a transporter for neutral amino acids that has recently been implicated in mood and metabolic disorders. It is predominantly expressed in the brain but little is otherwise known about its function. In order to identify inhibitors for this transporter we screened a library of different 3133 bioactive compounds. Loratadine, a clinically used histamine H1 receptor antagonist, was identified as a selective inhibitor of B0AT2 with an IC50 of 4 μM while being less active or inactive against several other members of the SLC6 family. Reversible inhibition of B0AT2 was confirmed by electrophysiology. A series of loratadine analogs was synthesized to get insight into the structure-activity relationships. Our studies provide the first chemical tool for B0AT2

Label-free versus conventional cellular assays: functional investigations on the human histamine H1 receptor

A set of histamine H-1 receptor (H-1 R) agonists and antagonists was characterized in functional assays, using dynamic mass redistribution (DMR), electric cell-substrate impedance sensing (ECIS) and various signaling pathway specific readouts (Fura-2 and aequorin calcium assays, arrestin recruitment (luciferase fragment complementation) assay, luciferase gene reporter assay). Data were gained from genetically engineered HEK293T cells and compared with reference data from GTPase assays and radioligand binding. Histamine and the other H-1 R agonists gave different assay-related pEC(50) values, however, the order of potency was maintained. In the luciferase fragment complementation assay, the H1R preferred beta-arrestin2 over beta-arrestin1. The calcium and the impedimetric assay depended on G(q) coupling of the H1R, as demonstrated by complete inhibition of the histamine-induced signals in the presence of the Gq inhibitor FR900359 (UBO-QIC). Whereas partial inhibition by FR900359 was observed in DMR and the gene reporter assay, pertussis toxin substantially decreased the response in DMR, but increased the luciferase signal, reflecting the contribution of both, Gq and Gi, to signaling in these assays. For antagonists, the results from DMR were essentially compatible with those from conventional readouts, whereas the impedance-based data revealed a trend towards higher pK(b) values. ECIS and calcium assays apparently only reflect Gq signaling, whereas DMR and gene reporter assays appear to integrate both, G(q) and G(i) mediated signaling. The results confirm the value of the label-free methods, DMR and ECIS, for the characterization of H1R ligands. Both noninvasive techniques are complementary to each other, but cannot fully replace reductionist signaling pathway focused assays. (C) 2016 Elsevier Ltd. All rights reserved

Loratadine and Analogues: Discovery and Preliminary Structure–Activity Relationship of Inhibitors of the Amino Acid Transporter B⁰AT2

B⁰AT2, encoded by the SLC6A15 gene, is a transporter for neutral amino acids that has recently been implicated in mood and metabolic disorders. It is predominantly expressed in the brain, but little is otherwise known about its function. To identify inhibitors for this transporter, we screened a library of 3133 different bioactive compounds. Loratadine, a clinically used histamine H₁ receptor antagonist, was identified as a selective inhibitor of B⁰AT2 with an IC₅₀ of 4 μM while being less active or inactive against several other members of the SLC6 family. Reversible inhibition of B⁰AT2 was confirmed by electrophysiology. A series of loratadine analogues were synthesized to gain insight into the structure–activity relationships. Our studies provide the first chemical tool for B⁰AT2