Current Pharmaceutical Design - Volume 23, Issue 1, 2017

Background: Productivity in drug R continues seeing significant attrition in clinical stage testing. Approval of new molecular entities proceeds with slow pace specifically when it comes to chronic, age-related diseases, calling for new conceptual approaches, methodological implementation and organizational adoption in drug development. Methods: Detailed phenotyping of disease presentation together with comprehensive representation of drug mechanism of action is considered as a path forward, and a big data spectrum has become available covering behavioral, clinical and molecular characteristics, the latter combining reductionist and explorative strategies. On this basis integrative analytics in the realm of Systems Biology has emerged, essentially aiming at traversing associations into causal relationships for bridging molecular disease specifics and clinical phenotype surrogates and finally explaining drug response and outcome. Results: From a conceptual perspective bottom-up modeling approaches are available, with dynamical hierarchies as formalism capable of describing clinical findings as emergent properties of an underlying molecular process network comprehensively resembling disease pathology. In such representation biomarker candidates serve as proxy of a molecular process set, at the interface of a corresponding representation of drug mechanism of action allowing patient stratification and prediction of drug response. In practical implementation network analytics on a protein coding gene level has provided a number of example cases for matching disease presentation and drug molecular effect, and workflows combining computational hypothesis generation and experimental evaluation have become available for systematically optimizing biomarker candidate selection. Conclusion: With biomarker-based enrichment strategies in adaptive clinical trials, implementation routes for tackling development attrition are provided. Predictive biomarkers add precision in drug development and as companion diagnostics in clinical practice.

Background: Non-small-cell lung cancer (NSCLC) is an aggressive neoplasm with a poor survival and novel therapies are urgently needed. The study of deregulated micro- RNAs (dereg-miRs) could constitute a strategy helping to detect specific genes playing a relevant role in the disease. Thus, the oncoproteins encoded by these genes could be exploited as novel therapeutic targets to be inhibited by small molecules, aptamers, or monoclonal antibodies. Methods: The present review is focused on candidate genes having convincing biological evidences to be both bona fide targets for dereg-miRs and playing a role in NSCLC progression. These genes were evaluated according to the molecular pathway they belong. Moreover, in the attempt to provide an even broader list of candidate therapeutic targets for NSCLC, the full list of genes was analyzed using the online tool Interactome DB. Results: Among the identified targets, some of them belong to p53 or MAP kinase signaling pathways, and others include caspases, MCL1, and BCL2L2 (playing a role in apoptosis), ZEB1, ZEB2, and USP25 (epithelial-to-mesenchymal transition), EZH2, SOX9, and HOXA5 (differentiation), Paxillin, LIMK1 and MTDH (cytoskeleton remodeling), and HDGF (angiogenesis). In addition, other targets, such as TIMP-2, PIM-1, and components of the IGF-signaling pathways were suggested following the interactome analysis. Conclusion: Studies on dereg-miRs helped to identify a set of genes whose encoded proteins could constitute candidates for future therapeutic approaches.

Background: Hedgehog signaling pathway is a developmental pathway mostly inactive in adult tissues, with the exception of stem cells. It is often found upregulated in various tumors, and associated with cancer stem cell maintenance. Methods: This review focuses on different aspects of Hedgehog activation in tumors, with special emphasis on ovarian tumors and their treatment. Results: Mutations in pathway components lead to a series of developmental malformations and syndromes. Aberrant activation of the pathway can be caused by mutations, noncanonical transcriptional regulation, or epigenetic changes. Conclusion: This pathway is an interesting target in cancer therapy, especially when combined with therapies targeting other signaling pathways. Combination therapy can be used to bypass resistance or to target cancer stem cells in a more efficient way.

Background: Casein kinase II (CK2) is a pro-oncogenic protein, which is emerging as a promising therapeutic target in cancer. Recent studies have revealed an important role for CK2 in tumorigenesis. High levels of CK2 are noted in many malignancies including leukemia. Use of CK2 inhibitors in various malignancies including breast, prostate, and lung cancer are being tested. Although many CK2 inhibitors exist, only a few have emerged as selective inhibitors that are potent and effective. CX-4945 is a selective, orallybioavailable small molecule inhibitor, which has shown encouraging results in pre-clinical models of leukemia. Methods: In this review we will elaborate on the structure and physiological function of the CK2 protein as well as its role in cancer. We will review, in depth, the role of CK2 in leukemia and its mechanisms of tumorigenesis via phosphorylation of the tumor suppressor protein Ikaros. We will discuss both the importance of Ikaros in leukemia suppression and the restoration of Ikaros’ tumor suppressor function after CK2 inhibition by CX-4945 (a CK2-specific inhibitor). Results: CK2 is an oncogene that is overexpressed in hematological malignancies. In high risk Pre-B ALL, CK2 phosphorylates Ikaros tumor suppressor and promotes leukemogenesis. Inhibition of CK2 using CX4945 restores Ikaros function and leads to anti leukemic effects in vitro and in pre-clinical leukemia models. Conclusion: CK2 is an attractive target in treatment of various cancers. Currently only a few specific CK2 inhibitors are available. Preclinical studies using CK2 inhibitor, CX4945 in high risk pediatric leukemias have shown promising results and warrants further testing in other types of leukemia.

Background: Notch is a multifaceted protein that plays a fundamental role in fetal development and tissue homeostasis by directing many cellular functions, including cell growth and differentiation, cell fate determination and regulation of stem cells maintenance. The Notch family consists of four receptors (Notch 1-4) and five ligands (Jagged1-2 and Delta-like 1-3-4) widely expressed in human tissues. Given the crucial contribution of Notch signaling in many physiological processes, it is not surprising that a variety of human malignancies is characterized by a dysregulation of one or more components of this pathway. Methods: In this review, we are going to provide a broad overview on the role of Notch pathway in solid and hematological malignancies and a survey on possible Notch-directed therapeutic strategies. Results: We present the most recent findings indicating that Notch signaling dysregulation in human cancers may be due to genetic and epigenetic alterations or to the interactions with other oncogenic pathways. Furthermore, Notch activity may have an oncogenic or a tumor suppressor effect. Finally, we describe the latest preclinical and clinical studies concerning the different pharmacological approaches targeting Notch. Conclusion: The provided evidence confirms the importance of Notch pathway in human malignancies indicating that a strong rationale exists for the development of a Notch-tailored therapy.

Background: Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders of hematopoietic system, characterized by genetic, epigenetic or microenvironmental alterations of aging hematopoietic stem cells. Pathophysiology of MDS comprises the suppression of normal hematopoiesis and reduced myeloid progenitor cells differentiation, with the main consequence of peripheral cytopenias and increased risk to evolution in acute myeloid leukemia (AML). Method: This review summarizes the evolving understanding of the role of genetic and epigenetic alterations involved in pathogenesis and current and future strategies for therapeutic targeting in myelodysplastic syndromes. Results: In addition to molecular characteristics, immune and microenvironmental factors in bone marrow of MDS patients may further modify the MDS manifestations, its clinical presentation, disease course, risk of transformation to AML and prognosis of MDS, as well as response to therapy. Current clinical response to therapy approaches are exerted both by epigenetic alterations and by induction of apoptosis. Conclusion: Future treatment strategies in preclinical and clinical investigations are directed towards new dosing schedules of existing drugs, new genetic and epigenetic targets and combination of different agents, including hypomethylation agents and histone deacetylase inhibitors.

Background: Hepatocellular carcinoma (HCC) represents the most common malignant liver tumor in humans, which incidence and mortality have increased in Europe and United States in the last years. Most patients are diagnosed at an advanced stage, when it is not amenable to curative therapies, so there is an urgent need for new, more effective therapeutic tools and strategies. The molecular mechanisms of hepatocarinogenesis and HCC progression have been increasingly understood with intense research in recent years. Methods: The goal of this work is to discuss the different signalling pathways as important potential therapeutic targets. Results: Disruption of pathways known to play roles in HCC, such as Wnt/β-catenin, Hedgehog, RAF/MEK/ERK, tryosine kinase receptor-related pathway, Met-HGF, VEGF/ VEGF and ROR signalling pathways may be seminal for liver oncogenesis. Conclusion: This review reveals that oncogenes, especially microRNAs that are conserved across species and interfere with signalling pathways might be used as promising strategies for halting or reversing the progression of HCC.

Background: Deletion of phenylalanine 508 is the most frequent mutation causing cystic fibrosis. It causes multiple defects: 1) misfolding of the protein causing retention at the ER (processing defect); 2) reduced channel activity (gating defect); 3) reduced plasma membrane residency time due to increased internalization rate and defective recycling. Methods: Druggability of F508del-CFTR was demonstrated by several studies. Correctors are molecules able to improve maturation and trafficking to the membrane of F508del- CFTR. Correctors could act as pharmacological chaperones or as proteostasis regulators. Pharmacological chaperones act directly on mutant CFTR, while proteostasis regulators modify the proteostasis environment leading to beneficial effects on CFTR maturation. Results: The use of a single compound is not sufficient to promote a therapeutically relevant F508del-CFTR rescue. Drug therapy for CF will require combinations of correctors exploiting different mechanisms of action, i.e. pharmacological chaperones combined together or with a proteostasis regulator. Conclusion: Development of more effective CF drugs could therefore rely on a better understanding of the molecular events underlying CFTR processing/degradation. This review will focus on most promising pathways and related targets for the development of novel CF pharmacotherapies.

Background: The field of bile acid research has become tremendously active. Bile acids have been shown to act as signaling molecules that are involved in many metabolic processes, but their role in carcinogenesis is also emerging. Methods: The aim of this review was to summarize the present knowledge in the innovative field of bile acids pharmacology, to reveal the novel mechanisms of their action, particularly focusing on clinically relevant aspects, and to evaluate the role of both genetic and epigenetic variation in genes encoding bile acid-activated receptors in determining the therapy outcome. Results: Most effects of bile acids are mediated by both nuclear and G protein-coupled receptors. Three natural bile acids have already been registered for the use in humans, but various semi-synthetic bile acid analogues with improved pharmacokinetic and pharmacodynamic properties have been developed, which opens up new avenues in pharmacotherapy. Many efforts have been made to evaluate the impact of nuclear receptors on inter-individual variation in responses to drugs, since nuclear receptors are significant mediators between environmental stimuli and pharmacokinetics. Genetic variation of bile acid-activated receptors is associated with both benign and malignant diseases, in terms of disease risk and severity, but also with pharmacokinetics and therapy outcome. Furthermore, the activity of these receptors may be masked or amplified by epigenetic modifications. Conclusion: Both genetic and epigenetic factors may alter complex and intricate network of bile acid signaling pathways, contributing to the development of several metabolic and non-metabolic diseases and altered activities of drug-metabolizing enzymes and transporters. These polymorphisms and epigenetic modifications may also impact the effectiveness and pharmacokinetics of bile acid analogues, which must be taken into account during the development of these compounds as novel therapeutic agents.