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The increasing cost of drug development together with a significant drop in the number of new drug approvals raises the need for innovative approaches for target identification and efficacy prediction. Here, we take advantage of our increasing understanding of the network-based origins of diseases to introduce a drug-disease proximity measure that quantifies the interplay between drugs targets and diseases. By correcting for the known biases of the interactome, proximity helps us uncover the therapeutic effect of drugs, as well as to distinguish palliative from effective treatments. Our analysis of 238 drugs used in 78 diseases indicates that the therapeutic effect of drugs is localized in a small network neighborhood of the disease genes and highlights efficacy issues for drugs used in Parkinson and several inflammatory disorders. Finally, network-based proximity allows us to predict novel drug-disease associations that offer unprecedented opportunities for drug repurposing and the detection of adverse effects. Attempts to predict novel use for existing drugs rarely consider information on the impact on the genes perturbed in a given disease. Here, the authors present a novel network-based drug-disease proximity measure that provides insight on gene specific therapeutic effect of drugs and may facilitate drug repurposing.

Key Points Integrin signalling regulates diverse functions in tumour cells, including migration, invasion, proliferation and survival. In several tumour types, the expression of particular integrins correlates with increased disease progression and decreased patient survival. In addition to tumour cells, integrins are also found on tumour-associated host cells, such as the vascular endothelium, perivascular cells, fibroblasts, bone marrow-derived cells and platelets. Integrin signalling crucially regulates the contribution of these cell types to cancer progression. Therefore, integrin antagonists may inhibit tumour progression by blocking crucial signalling events in both the tumour microenvironment and the tumour cells themselves. Integrins have a profound influence on tumour cells, both in the ligated and unligated states, in which they regulate tumour cell survival and malignancy. Although integrins alone are not oncogenic, recent data have found that some oncogenes may require integrin signalling for their ability to initiate tumour growth and invasion. These effects may be due to the important contribution of integrin signalling in maintaining the cancer stem cell population in a given tumour. Crosstalk between integrins and growth factor or cytokine receptors on both tumour and host cell types is vital for many aspects of tumour progression. Mechanisms of crosstalk include both direct and indirect association of integrins with growth factor or cytokine receptors, which affects the expression, ligand affinity and signalling of the receptors. The important contribution of integrins to the biology of both tumour cells and tumour-associated cell types has made them appealing targets for the design of specific therapeutics. Of particular interest, the integrin αv inhibitor cilengitide is now in a Phase III clinical trial in glioblastoma, and because this is the first integrin antagonist to achieve this milestone it places anti-integrin therapy on the doorstep of clinical availability. In addition to their use as therapeutic targets, integrins can be imaging biomarkers for assessing the efficacy of anti-angiogenic and anti-tumour agents. Integrin-targeted nanoparticles with a diverse array of anti-tumour payloads also represent a particularly promising area of research that may decrease the toxicities associated with systemic delivery of radiation or chemotherapy. The integrins regulate a diverse array of cellular functions that are crucial to the initiation, progression and metastasis of solid tumours. This Review discusses the exciting developments in targeting integrins, including the recent initiation of a Phase III trial for an integrin antagonist in patients with glioblastoma. The integrin family of cell adhesion receptors regulates a diverse array of cellular functions crucial to the initiation, progression and metastasis of solid tumours. The importance of integrins in several cell types that affect tumour progression has made them an appealing target for cancer therapy. Integrin antagonists, including the αvβ3 and αvβ5 inhibitor cilengitide, have shown encouraging activity in Phase II clinical trials and cilengitide is currently being tested in a Phase III trial in patients with glioblastoma. These exciting clinical developments emphasize the need to identify how integrin antagonists influence the tumour and its microenvironment.

Therapeutic nanoparticles (TNPs) aim to deliver drugs more safely and effectively to cancers, yet clinical results have been unpredictable owing to limited in vivo understanding. Here we use single-cell imaging of intratumoral TNP pharmacokinetics and pharmacodynamics to better comprehend their heterogeneous behaviour. Model TNPs comprising a fluorescent platinum(IV) pro-drug and a clinically tested polymer platform (PLGA- b -PEG) promote long drug circulation and alter accumulation by directing cellular uptake toward tumour-associated macrophages (TAMs). Simultaneous imaging of TNP vehicle, its drug payload and single-cell DNA damage response reveals that TAMs serve as a local drug depot that accumulates significant vehicle from which DNA-damaging Pt payload gradually releases to neighbouring tumour cells. Correspondingly, TAM depletion reduces intratumoral TNP accumulation and efficacy. Thus, nanotherapeutics co-opt TAMs for drug delivery, which has implications for TNP design and for selecting patients into trials. Drug-loaded nanoparticles allow controlled release and enhanced delivery, yet understanding in vivo behavior has been difficult. Here, the authors develop a platinum prodrug coupled to a polymer platform, and use intravital imaging to show that the nanoparticle accumulates in macrophages, from the which drug redistributes to neighboring tumour cells.

Cancer cells, compared with normal cells, are under oxidative stress associated with the increased generation of reactive oxygen species (ROS) including H 2 O 2 and are also susceptible to further ROS insults. Cancer cells adapt to oxidative stress by upregulating antioxidant systems such as glutathione to counteract the damaging effects of ROS. Therefore, the elevation of oxidative stress preferentially in cancer cells by depleting glutathione or generating ROS is a logical therapeutic strategy for the development of anticancer drugs. Here we report a dual stimuli-responsive hybrid anticancer drug QCA, which can be activated by H 2 O 2 and acidic pH to release glutathione-scavenging quinone methide and ROS-generating cinnamaldehyde, respectively, in cancer cells. Quinone methide and cinnamaldehyde act in a synergistic manner to amplify oxidative stress, leading to preferential killing of cancer cells in vitro and in vivo . We therefore anticipate that QCA has promising potential as an anticancer therapeutic agent. Cancer cells have elevated levels of reactive oxygen species. Here the authors show that cancer cells can be selectively killed in vitro and in vivo by an oxidative stress-activated drug, which amplifies the generation of reactive oxygen species while blocking the cells’ antioxidant defense.

Unprecedented advances have been made in the treatment of cancer through the use of immune checkpoint blockade, with approval of several checkpoint blockade regimens spanning multiple cancer types. However, responses to this form of therapy are not universal, and insights are clearly needed to identify optimal biomarkers of response and to combat mechanisms of therapeutic resistance. A working knowledge of the hallmarks of cancer yields insight into responses to immune checkpoint blockade, although the focus of this is rather tumour-centric and additional factors are pertinent, including host immunity and environmental influences. Herein, we describe the foundation for pillars and hallmarks of response to immune checkpoint blockade, with a discussion of their relevance to immune monitoring and mechanisms of resistance. Evolution of this understanding will ultimately help guide treatment strategies to enhance therapeutic responses.

The Cancer Cell Line Encyclopedia presents the first results from a large-scale screen of some 947 cancer cell lines with 24 anticancer drugs, with the aim of identifying specific genomic alterations and gene expression profiles associated with selective sensitivity or resistance to potential therapeutic agents. Large-scale cancer cell line screening Cancer cell lines are widely used as preclinical models to gain mechanistic and therapeutic insight. Two manuscripts in this issue describe the large-scale genetic and pharmacological characterization of human cancer cell lines. Each group characterized collections of several-hundred cell lines using different platforms and analytical methods. Their results are complementary, and confirm that many human cell lines capture the genomic diversity of their respective cancers. Initial findings include the identification of a number of potential markers of drug sensitivity and resistance. For example, Garnett et al . report an association between EWS-FLI1 gene translocations, frequently found in Ewing's sarcoma, and sensitivity to PARP inhibitors, a class of drug currently in clinical trials for other cancer types. Barretina et al . report a possible association between SLFN11 expression and sensitivity to topoisomerase inhibitors. The systematic translation of cancer genomic data into knowledge of tumour biology and therapeutic possibilities remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacological annotation is available 1 . Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacological profiles for 24 anticancer drugs across 479 of the cell lines, this collection allowed identification of genetic, lineage, and gene-expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS -mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Together, our results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of ‘personalized’ therapeutic regimens 2 .

Background: Obesity is strongly associated with prevalence of obstructive sleep apnea (OSA), and weight loss has been shown to reduce disease severity. Objective: To investigate whether liraglutide 3.0 mg reduces OSA severity compared with placebo using the primary end point of change in apnea–hypopnea index (AHI) after 32 weeks. Liraglutide’s weight loss efficacy was also examined. Subjects/Methods: In this randomized, double-blind trial, non-diabetic participants with obesity who had moderate (AHI 15–29.9 events h −1 ) or severe (AHI ⩾30 events h −1 ) OSA and were unwilling/unable to use continuous positive airway pressure therapy were randomized for 32 weeks to liraglutide 3.0 mg ( n =180) or placebo ( n =179), both as adjunct to diet (500 kcal day −1 deficit) and exercise. Baseline characteristics were similar between groups (mean age 48.5 years, males 71.9%, AHI 49.2 events h −1 , severe OSA 67.1%, body weight 117.6 kg, body mass index 39.1 kg m −2 , prediabetes 63.2%, HbA 1c 5.7%). Results: After 32 weeks, the mean reduction in AHI was greater with liraglutide than with placebo (−12.2 vs −6.1 events h −1 , estimated treatment difference: −6.1 events h −1 (95% confidence interval (CI), −11.0 to −1.2), P =0.0150). Liraglutide produced greater mean percentage weight loss compared with placebo (−5.7% vs −1.6%, estimated treatment difference: −4.2% (95% CI, −5.2 to −3.1%), P <0.0001). A statistically significant association between the degree of weight loss and improvement in OSA end points ( P <0.01, all) was demonstrated post hoc . Greater reductions in glycated hemoglobin (HbA 1c ) and systolic blood pressure (SBP) were seen with liraglutide versus placebo (both P <0.001). The safety profile of liraglutide 3.0 mg was similar to that seen with doses ⩽1.8 mg. Conclusions: As an adjunct to diet and exercise, liraglutide 3.0 mg was generally well tolerated and produced significantly greater reductions than placebo in AHI, body weight, SBP and HbA 1c in participants with obesity and moderate/severe OSA. The results confirm that weight loss improves OSA-related parameters.

Concerted multidisciplinary efforts have led to the development of Cyclin-Dependent Kinase inhibitors (CDKi’s) as small molecule drugs and chemical probes of intracellular CDK function. However, conflicting data has been reported on the inhibitory potency of CDKi’s and a systematic characterization of affinity and selectivity against intracellular CDKs is lacking. We have developed a panel of cell-permeable energy transfer probes to quantify target occupancy for all 21 human CDKs in live cells, and present a comprehensive evaluation of intracellular isozyme potency and selectivity for a collection of 46 clinically-advanced CDKi’s and tool molecules. We observed unexpected intracellular activity profiles for a number of CDKi’s, offering avenues for repurposing of highly potent molecules as probes for previously unreported targets. Overall, we provide a broadly applicable method for evaluating the selectivity of CDK inhibitors in living cells, and present a refined set of tool molecules to study CDK function. Cyclin-dependent kinase (CDK) inhibitors are widely used both in the clinic and for basic research aimed at dissecting the specific cellular functions of specific CDKs. Here, the authors report the development of a panel of fluorescent reporter probes and provide a comprehensive profile of the inhibitory activity of several CDK inhibitors towards all 21 CDKs in living cells.

Key Points Heat shock protein 90 (HSP90) is a molecular chaperone of numerous oncoproteins. Therefore, cancer cells can be considered to be 'addicted' to this molecule. HSP90 is also a mediator of cellular homeostasis. As such, it facilitates numerous transient low-affinity protein–protein interactions that have only recently been identified using bioinformatic and proteomic techniques. Although primarily a cytoplasmic protein, HSP90 affects diverse nuclear processes, including transcription, chromatin remodelling and DNA damage-induced mutation. HSP90 is a conformationally dynamic protein. ATP binding to the amino (N) domain and its subsequent hydrolysis by HSP90 drive a conformational cycle that is essential for chaperone activity. In eukaryotes, co-chaperones and post-translational modifications regulate both client interactions with HSP90 and HSP90 ATPase activity. Co-chaperones and post-translational modifications can also affect the efficacy of HSP90 inhibitors. HSP90 inhibitors currently under clinical evaluation interact with the N domain ATP-binding pocket, prevent ATP binding, and stop the chaperone cycle, leading to client protein degradation. Because of the HSP90 client repertoire, HSP90 inhibitors may combat oncogene switching, which is an important mechanism of tumour escape from tyrosine kinase inhibitors. Derivatives of the coumarin antibiotic novobiocin represent an alternative strategy for inhibiting HSP90 by targeting a unique carboxy-terminal (C) domain. Optimal development of HSP90-directed therapeutics will depend on synthesizing information gained from careful genetic analysis of primary and metastatic tumours with an understanding of the unique environmental context in which the tumour is thriving at the expense of the host. Numerous oncoproteins depend on the molecular chaperone heat shock protein 90 (HSP90). However, the optimal use of HSP90-targeted therapeutics will depend on understanding the complexity of HSP90 regulation and the degree to which the chaperone participates in both neoplastic and normal cellular physiology. The molecular chaperone heat shock protein 90 (HSP90) has been used by cancer cells to facilitate the function of numerous oncoproteins, and it can be argued that cancer cells are 'addicted' to HSP90. However, although recent reports of the early clinical efficacy of HSP90 inhibitors are encouraging, the optimal use of HSP90-targeted therapeutics will depend on understanding the complexity of HSP90 regulation and the degree to which HSP90 participates in both neoplastic and normal cellular physiology.