The Impact of Bioactive Lipids on Cardiovascular Development

Lysophospholipids comprise a group of bioactive molecules with multiple biological functions. The cardinal members of this signalling molecule group are sphingosylphosphorylcholine (SPC), lysophosphatidic acid (LPA), and sphingosine 1-phosphate (S1P) which are, at least in part, homologous to each other. Bioactive lipids usually act via G-protein coupled receptors (GPCRs), but can also function as direct intracellular messengers. Recently, it became evident that bioactive lipids play a role during cellular differentiation development. SPC induces mesodermal differentiation of mouse ES cells and differentiation of promyelocytic leukemia cells, by a mechanism being critically dependent on MEK-ERK signalling. LPA stimulates the clonal expansion of neurospheres from neural stem/progenitor cells and induces c-fos via activation of mitogen- and stress-activated protein kinase 1 (MSK1) in ES cells. S1P acts on hematopoietic progenitor cells as a chemotactic factor and has also been found to be critical for cardiac and skeletal muscle regeneration. Furthermore, S1P promotes cardiogenesis and similarly activates Erk signalling in mouse ES cells. Interestingly, S1P may also act to maintain human stem cell pluripotency. Both LPA and S1P positively regulate the proliferative capacity of murine ES cells. In this paper we will focus on the differential and developmental impact of lysophospholipids on cardiovascular development

Tumor biology and cancer therapy – an evolving relationship

The aim of palliative chemotherapy is to increase survival whilst maintaining maximum quality of life for the individual concerned. Although we are still continuing to explore the optimum use of traditional chemotherapy agents, the introduction of targeted therapies has significantly broadened the therapeutic options. Interestingly, the results from current trials put the underlying biological concept often into a new, less favorable perspective. Recent data suggested that altered pathways underlie cancer, and not just altered genes. Thus, an effective therapeutic agent will sometimes have to target downstream parts of a signaling pathway or physiological effects rather than individual genes. In addition, over the past few years increasing evidence has suggested that solid tumors represent a very heterogeneous group of cells with different susceptibility to cancer therapy. Thus, since therapeutic concepts and pathophysiological understanding are continuously evolving a combination of current concepts in tumor therapy and tumor biology is needed. This review aims to present current problems of cancer therapy by highlighting exemplary results from recent clinical trials with colorectal and pancreatic cancer patients and to discuss the current understanding of the underlying reasons

An Inducible Expression System of the Calcium-Activated Potassium Channel 4 to Study the Differential Impact on Embryonic Stem Cells

Rationale. The family of calcium-activated potassium channels consists of four members with varying biological functions and conductances. Besides membrane potential modulation, SK channels have been found to be involved in cardiac pacemaker cell development from ES cells and morphological shaping of neural stem cells. Objective. Distinct SK channel subtype expression in ES cells might elucidate their precise impact during cardiac development. We chose SK channel subtype 4 as a potential candidate influencing embryonic stem cell differentiation. Methods. We generated a doxycycline inducible mouse ES cell line via targeted homologous recombination of a cassette expressing a bicistronic construct encoding SK4 and a fluorophore from the murine HPRT locus. Conclusion. We characterized the mouse ES cell line iSK4-AcGFP. The cassette is readily expressed under the control of doxycycline, and the overexpression of SK4 led to an increase in cardiac and pacemaker cell differentiation thereby serving as a unique tool to characterize the cell biological variances due to specific SK channel overexpression

Significantly improved precision of cell migration analysis in time-lapse video microscopy through use of a fully automated tracking system

<p>Abstract</p> <p>Background</p> <p>Cell motility is a critical parameter in many physiological as well as pathophysiological processes. In time-lapse video microscopy, manual cell tracking remains the most common method of analyzing migratory behavior of cell populations. In addition to being labor-intensive, this method is susceptible to user-dependent errors regarding the selection of "representative" subsets of cells and manual determination of precise cell positions.</p> <p>Results</p> <p>We have quantitatively analyzed these error sources, demonstrating that manual cell tracking of pancreatic cancer cells lead to mis-calculation of migration rates of up to 410%. In order to provide for objective measurements of cell migration rates, we have employed multi-target tracking technologies commonly used in radar applications to develop fully automated cell identification and tracking system suitable for high throughput screening of video sequences of unstained living cells.</p> <p>Conclusion</p> <p>We demonstrate that our automatic multi target tracking system identifies cell objects, follows individual cells and computes migration rates with high precision, clearly outperforming manual procedures.</p

LICC: L-BLP25 in patients with colorectal carcinoma after curative resection of hepatic metastases--a randomized, placebo-controlled, multicenter, multinational, double-blinded phase II trial

Background: 15-20% of all patients initially diagnosed with colorectal cancer develop metastatic disease and surgical resection remains the only potentially curative treatment available. Current 5-year survival following R0-resection of liver metastases is 28-39%, but recurrence eventually occurs in up to 70%. To date, adjuvant chemotherapy has not improved clinical outcomes significantly. The primary objective of the ongoing LICC trial (L-BLP25 In Colorectal Cancer) is to determine whether L-BLP25, an active cancer immunotherapy, extends recurrence-free survival (RFS) time over placebo in colorectal cancer patients following R0/R1 resection of hepatic metastases. L-BLP25 targets MUC1 glycoprotein, which is highly expressed in hepatic metastases from colorectal cancer. In a phase IIB trial, L-BLP25 has shown acceptable tolerability and a trend towards longer survival in patients with stage IIIB locoregional NSCLC. Methods: This is a multinational, phase II, multicenter, randomized, double-blind, placebo-controlled trial with a sample size of 159 patients from 20 centers in 3 countries. Patients with stage IV colorectal adenocarcinoma limited to liver metastases are included. Following curative-intent complete resection of the primary tumor and of all synchronous/metachronous metastases, eligible patients are randomized 2:1 to receive either L-BLP25 or placebo. Those allocated to L-BLP25 receive a single dose of 300 mg/m2 cyclophosphamide (CP) 3 days before first L-BLP25 dose, then primary treatment with s.c. L-BLP25 930 mug once weekly for 8 weeks, followed by s.c. L-BLP25 930 mug maintenance doses at 6-week (years 1&2) and 12-week (year 3) intervals unless recurrence occurs. In the control arm, CP is replaced by saline solution and L-BLP25 by placebo. Primary endpoint is the comparison of recurrence-free survival (RFS) time between groups. Secondary endpoints are overall survival (OS) time, safety, tolerability, RFS/OS in MUC-1 positive cancers. Exploratory immune response analyses are planned. The primary endpoint will be assessed in Q3 2016. Follow-up will end Q3 2017. Interim analyses are not planned. Discussion: The design and implementation of such a vaccination study in colorectal cancer is feasible. The study will provide recurrence-free and overall survival rates of groups in an unbiased fashion. Trial Registration EudraCT Number 2011-000218-2

Force-dependent integrin–cytoskeleton linkage formation requires downregulation of focal complex dynamics by Shp2

As cells encounter new regions of the substrate, they develop bonds with new matrix molecules for migration, matrix remodeling and force generation. How cells orchestrate the assembly of adhesion sites is only partially understood. Here we show that fibroblasts deficient in the SH2 domain containing protein tyrosine phosphatase 2 (Shp2) have an increased number of immature focal complexes deficient in α-actinin. Inhibition of FAK restored α-actinin to focal complexes, whereas inhibition of RhoA did not. In correlation, adhesion site dynamics, measured by fluorescence recovery after photobleaching (FRAP) of GFP–paxillin and GFP–vinculin were dramatically increased in Shp2(–/–) cells and restored to normal by FAK inhibition. Shp2(–/–) cells failed to strengthen initial integrin–cytoskeleton linkages, as measured by optical tweezers and large bead assays, and were rescued by inhibition of FAK. In contrast, affinity modulation of adhesion receptors was unaffected. In addition, reinforcement correlated with α-actinin assembly through decreased dynamics. This shows for the first time that adhesion site dynamics are regulated during adhesion formation and that force-dependent strengthening of integrin–cytoskeleton linkages is correlated with α-actinin assembly and decreased adhesion site dynamics

Role of the Regulatory Domain of Protein Kinase D2 in Phorbol Ester Binding, Catalytic Activity, and Nucleocytoplasmic Shuttling

Protein kinase D2 (PKD2) belongs to the PKD family of serine/threonine kinases that is activated by phorbol esters and G protein-coupled receptors (GPCRs). Its C-terminal regulatory domain comprises two cysteine-rich domains (C1a/C1b) followed by a pleckstrin homology (PH) domain. Here, we examined the role of the regulatory domain in PKD2 phorbol ester binding, catalytic activity, and subcellular localization: The PH domain is a negative regulator of kinase activity. C1a/C1b, in particular C1b, is required for phorbol ester binding and gastrin-stimulated PKD2 activation, but it has no inhibitory effect on the catalytic activity. Gastrin triggers nuclear accumulation of PKD2 in living AGS-B cancer cells. C1a/C1b, not the PH domain, plays a complex role in the regulation of nucleocytoplasmic shuttling: We identified a nuclear localization sequence in the linker region between C1a and C1b and a nuclear export signal in the C1a domain. In conclusion, our results define the critical components of the PKD2 regulatory domain controlling phorbol ester binding, catalytic activity, and nucleocytoplasmic shuttling and reveal marked differences to the regulatory properties of this domain in PKD1. These findings could explain functional differences between PKD isoforms and point to a functional role of PKD2 in the nucleus upon activation by GPCRs

Combination of antiangiogenic therapy using the mTOR-inhibitor everolimus and low-dose chemotherapy for locally advanced and/or metastatic pancreatic cancer: a dose-finding study

Pancreatic adenocarcinomas are associated with a poor survival prognosis. Besides curative surgical resection, only limited therapies with modest impact are available. New evidence suggests that the mammalian target of rapamycin pathway may be involved in the pathogenesis of neuroendocrine tumors, and breast and renal cell cancer. The phase I study described here was therefore designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of escalating doses of the mammalian target of rapamycin inhibitor everolimus in combination with gemcitabine in patients with advanced pancreatic cancer. Eligible patients had histologically confirmed locally advanced and/or metastatic pancreatic carcinoma and were administered 5 mg everolimus every second day (cohort 1, 2, 3) or 5 mg daily (cohort 4, 5) in combination with escalating low-dose gemcitabine. It was found that if two patients showed DLTs, MTD was reached and gemcitabine dose escalation was stopped at this level. Twenty-seven patients were enrolled in the study (cohort 1: n=3; cohort 2: n=4; cohort 3: n=6; cohort 4: n=7; cohort 5: n=7) and received a maximum 600 mg gemcitabine/week. In cohort 5, two of the six patients experienced DLTs (grade 3 liver toxicity lasting for>7 days). MTD was measured as 400 mg/m2/week gemcitabine plus 5 mg/day everolimus. The MTD of a low-dose gemcitabine treatment in combination with everolimus was determined and no new safety concerns were identified in patients with advanced pancreatic cancer