Immunotherapy in multiple myeloma

The BDCA antibodies allowed reliable measurement of dendritic cell (DC) subsets and B cell numbers in the blood of normal subjects, and patients with MM throughout the disease course. The numbers of blood myeloid DC (BmDC) and blood plasmacytoid DC (BpDC) are low throughout the course of the disease, and only improve for a short period of time following autologous HSCT. Thalidomide therapy of patients with relapsed disease was associated with an increase in BmDC1 and BpDC numbers. Monocytes, mobilised at the time of stem cell collection, were used to produce mature DC (matDC) from MM patients and normal donors (ND). The matDC produced from MM patients were of poorer quality as compared to those from ND, despite using combinations of GM/IL-4, GM/IL-13, X4 and MIMIC in the production process. The combinations that contained the X4 maturation cocktail produced the best quality matDC. The DC/T cell system is abnormal in MM patients. Despite this, it is possible to produce antigen loaded mature MoDC from MM patients. When combined with T cell pre-stimulation and IL-2 expansion, these DC are capable of inducing anti-MM cytotoxic T cells, which exhibit considerable anti-MM cytolytic activity. However, the DC from MM patients still display abnormal chemokine receptor expression, which may inhibit their capability to migrate to lymph nodes in-vivo in order to generate these cytotoxic T cell responses. These observations will aid in the optimisation of DC based immune therapies for MM, and suggest that a combined immunotherapy approach using pre-stimulated T cells, MM Ag primed DC and IL-2 may produce better clinical responses in MM patients

A model of estrogen-related gene expression reveals non-linear effects in transcriptional response to tamoxifen

SynthSys is a Centre for Integrative Systems Biology (CISB) funded by BBSRC and EPSRC, reference BB/D019621/1.Background: Estrogen receptors alpha (ER) are implicated in many types of female cancers, and are the common target for anti-cancer therapy using selective estrogen receptor modulators (SERMs, such as tamoxifen). However, cell-type specific and patient-to-patient variability in response to SERMs (from suppression to stimulation of cancer growth), as well as frequent emergence of drug resistance, represents a serious problem. The molecular processes behind mixed effects of SERMs remain poorly understood, and this strongly motivates application of systems approaches. In this work, we aimed to establish a mathematical model of ER-dependent gene expression to explore potential mechanisms underlying the variable actions of SERMs. Results: We developed an equilibrium model of ER binding with 17 beta-estradiol, tamoxifen and DNA, and linked it to a simple ODE model of ER-induced gene expression. The model was parameterised on the broad range of literature available experimental data, and provided a plausible mechanistic explanation for the dual agonism/antagonism action of tamoxifen in the reference cell line used for model calibration. To extend our conclusions to other cell types we ran global sensitivity analysis and explored model behaviour in the wide range of biologically plausible parameter values, including those found in cancer cells. Our findings suggest that transcriptional response to tamoxifen is controlled in a complex non-linear way by several key parameters, including ER expression level, hormone concentration, amount of ER-responsive genes and the capacity of ER-tamoxifen complexes to stimulate transcription (e. g. by recruiting co-regulators of transcription). The model revealed non-monotonic dependence of ER-induced transcriptional response on the expression level of ER, that was confirmed experimentally in four variants of the MCF-7 breast cancer cell line. Conclusions: We established a minimal mechanistic model of ER-dependent gene expression, that predicts complex non-linear effects in transcriptional response to tamoxifen in the broad range of biologically plausible parameter values. Our findings suggest that the outcome of a SERM's action is defined by several key components of cellular micro-environment, that may contribute to cell-type-specific effects of SERMs and justify the need for the development of combinatorial biomarkers for more accurate prediction of the efficacy of SERMs in specific cell types.Publisher PDFPeer reviewe

Kinetic modelling of in vitro data of PI3K, mTOR1, PTEN enzymes and on-target inhibitors Rapamycin, BEZ235, and LY294002

The phosphatidylinositide 3-kinases (PI3K) and mammalian target of rapamycin-1 (mTOR1) are two key targets for anti-cancer therapy. Predicting the response of the PI3K/AKT/mTOR1 signalling pathway to targeted therapy is made difficult because of network complexities. Systems biology models can help explore those complexities but the value of such models is dependent on accurate parameterisation. Motivated by a need to increase accuracy in kinetic parameter estimation, and therefore the predictive power of the model, we present a framework to integrate kinetic data from enzyme assays into a unified enzyme kinetic model. We present exemplar kinetic models of PI3K and mTOR1, calibrated on in vitro enzyme data and founded on Michaelis-Menten (MM) approximation. We describe the effects of an allosteric mTOR1 inhibitor (Rapamycin) and ATP-competitive inhibitors (BEZ2235 and LY294002) that show dual inhibition of mTOR1 and PI3K. We also model the kinetics of phosphatase and tensin homolog (PTEN), which modulates sensitivity of the PI3K/AKT/mTOR1 pathway to these drugs. Model validation with independent data sets allows investigation of enzyme function and drug dose dependencies in a wide range of experimental conditions. Modelling of the mTOR1 kinetics showed that Rapamycin has an IC50 independent of ATP concentration and that it is a selective inhibitor of mTOR1 substrates S6K1 and 4EBP1: it retains 40% of mTOR1 activity relative to 4EBP1 phosphorylation and inhibits completely S6K1 activity. For the dual ATP-competitive inhibitors of mTOR1 and PI3K, LY294002 and BEZ235, we derived the dependence of the IC50 on ATP concentration that allows prediction of the IC50 at different ATP concentrations in enzyme and cellular assays. Comparison of the drug effectiveness in enzyme and cellular assays showed that some features of these drugs arise from signalling modulation beyond the on-target action and MM approximation and require a systems-level consideration of the whole PI3K/PTEN/AKT/mTOR1 network in order to understand mechanisms of drug sensitivity and resistance in different cancer cell lines. We suggest that using these models in systems biology investigation of the PI3K/AKT/mTOR1 signalling in cancer cells can bridge the gap between direct drug target action and the therapeutic response to these drugs and their combinations

Customizing the therapeutic response of signaling networks to promote antitumor responses by drug combinations

Drug resistance, de novo and acquired, pervades cellular signaling networks (SNs) from one signaling motif to another as a result of cancer progression and/or drug intervention. This resistance is one of the key determinants of efficacy in targeted anti-cancer drug therapy. Although poorly understood, drug resistance is already being addressed in combination therapy by selecting drug targets where SN sensitivity increases due to combination components or as a result of de novo or acquired mutations. Additionally, successive drug combinations have shown low resistance potential. To promote a rational, systematic development of combination therapies, it is necessary to establish the underlying mechanisms that drive the advantages of combination therapies, and design methods to determine drug targets for combination regimens. Based on a joint systems analysis of cellular SN response and its sensitivity to drug action and oncogenic mutations, we describe an in silico method to analyze the targets of drug combinations. Our method explores mechanisms of sensitizing the SN through a combination of two drugs targeting vertical signaling pathways. We propose a paradigm of SN response customization by one drug to both maximize the effect of another drug in combination and promote a robust therapeutic response against oncogenic mutations. The method was applied to customize the response of the ErbB/PI3K/PTEN/AKT pathway by combination of drugs targeting HER2 receptors and proteins in the down-stream pathway. The results of a computational experiment showed that the modification of the SN response from hyperbolic to smooth sigmoid response by manipulation of two drugs in combination leads to greater robustness in therapeutic response against oncogenic mutations determining cancer heterogeneity. The application of this method in drug combination co-development suggests a combined evaluation of inhibition effects together with the capability of drug combinations to suppress resistance mechanisms before they become clinically manifest

Patterns and processes in the epilithic communities of a stony lake shore.

PhDThis study on the littoral of Crosemere has shown that complex direct and indirect interactions exist between larvae of the gallery-building caddis Tinodes waeneri, the filamentous macro-alga Cladophora glomerata, and the larvae of several species of retreat-building chironomids. Co-existence between these species is facilitated by spatial and temporal patchiness in dispersal ability and behaviour by the dominant grazer/competitor Tinodes waeneri. Tinodes eats Cladophora and thus indirectly controls the abundance of chironomids which associate with the Cladophora mat. Adult oviposition under trees determines the initial distribution of Tinodes and several chironomids. While these latter can probably rapidly disperse by swimming, Tinodes dispersal is more limited. This creates spatial refugia for Cladophora and chironomids in areas of the littoral away from trees. Local-scale, temporal refugia are created by Cladophora being able to 'grow away' from Tinodes during periods in spring when Cladophora colonizes more vigorously than Tinodes. Local-scale spatial refugia are also created by modes' apparent reluctance to colonize taller stones. This spatial and temporal patchiness in species interactions in the littoral is set against a background of lake-wide, temporal variation which appears to constrain the entire littoral habitat. The summer stratification of Crosemere into upper and lower layers causes the surface waters, probably including also the littoral, to be seasonally nutrient-limited, particularly in nitrogen. This in turn will limit primary production in the littoral and thus also secondary production. The epilithic species studied all appeared to be food-limited in summer. The dominance of the Crosemere littoral by retreat-dwelling species may partly be due to their ability to recycle limited nutrients within or on their retreats and so to consume more algae than is otherwise available to mobile species.Natural Environment Research council (NERC

The Alestle - Vol. 58 No. 7 - 09/15/2005

Vol. 58 No.

Selling (un)real estate with "Shi(势)-nema": manipulation, not persuasion, in China's contemporary cinematic-cities

Investigating what has been called the mise-en-scene of Capitalism's Second Coming in China, this essay explores how cinematic principles have become divorced from the medium of cinema and can be found operating within contemporary Chinese urban spaces in order to increase the efficacy of real estate showroom settings. Specifically, we explore the effects of affectively distributed networks of human, architectural and nonhuman " actors " that appear to be arranged in such a way as to manipulate and impact the thoughts, feelings and actions of potential buyers. To best expose the effectiveness of these modern urban assemblages, we engineer an encounter between the Chinese concept of shi (势) – described by sinologist-philosopher François Julien as the " inherent potentiality at work in configuration " – and that of cinematicty, wherein the cinema and city are recognised as co-determining and mutually enabling site/ sights

Quantitative analysis of NRF2 pathway reveals key elements of the regulatory circuits underlying antioxidant response and proliferation of ovarian cancer cells

Cells are constantly exposed to Reactive Oxygen Species (ROS) produced both endogenously to meet physiological requirements and from exogenous sources. While endogenous ROS are considered as important signalling molecules, high uncontrollable ROS are detrimental. It is unclear how cells can achieve a balance between maintaining physiological redox homeostasis and robustly activate the antioxidant system to remove exogenous ROS. We have utilised a Systems Biology approach to understand how this robust adaptive system fulfils homeostatic requirements of maintaining steady-state ROS and growth rate, while undergoing rapid readjustment under challenged conditions. Using a panel of human ovarian and normal cell lines, we experimentally quantified and established interrelationships between key elements of ROS homeostasis. The basal levels of NRF2 and KEAP1 were cell line specific and maintained in tight correlation with their growth rates and ROS. Furthermore, perturbation of this balance triggered cell specific kinetics of NRF2 nuclear–cytoplasmic relocalisation and sequestration of exogenous ROS. Our experimental data were employed to parameterise a mathematical model of the NRF2 pathway that elucidated key response mechanisms of redox regulation and showed that the dynamics of NRF2-H2O2 regulation defines a relationship between half-life, total and nuclear NRF2 level and endogenous H2O2 that is cell line specific

Compensatory effects in the PI3K/PTEN/AKT signaling network following receptor tyrosine kinase inhibition

Overcoming de novo and acquired resistance to anticancer drugs that target signaling networks is a formidable challenge for drug design and effective cancer therapy. Understanding the mechanisms by which this resistance arises may offer a route to addressing the insensitivity of signaling networks to drug intervention and restore the efficacy of anticancer therapy. Extending our recent work identifying PTEN as a key regulator of Herceptin sensitivity, we present an integrated theoretical and experimental approach to study the compensatory mechanisms within the PI3K/PTEN/AKT signaling network that afford resistance to receptor tyrosine kinase (RTK) inhibition by anti-HER2 monoclonal antibodies. In a computational model representing the dynamics of the signaling network, we define a single control parameter that encapsulates the balance of activities of the enzymes involved in the PI3K/PTEN/AKT cycle. By varying this control parameter we are able to demonstrate both distinct dynamic regimes of behavior of the signaling network and the transitions between those regimes. We demonstrate resistance, sensitivity, and suppression of RTK signals by the signaling network. Through model analysis we link the sensitivity-to-resistance transition to specific compensatory mechanisms within the signaling network. We study this transition in detail theoretically by variation of activities of PTEN, PI3K, AKT enzymes, and use the results to inform experiments that perturb the signaling network using combinatorial inhibition of RTK, PTEN, and PI3K enzymes in human ovarian carcinoma cell lines. We find good alignment between theoretical predictions and experimental results. We discuss the application of the results to the challenges of hypersensitivity of the signaling network to RTK signals, suppression of drug resistance, and efficacy of drug combinations in anticancer therapy