Topics in Anti-Cancer Research

The use of TRAIL/APO2L, monoclonal antibodies or peptidomimetics targeting TRAIL receptors for cancer therapy holds great promise, due to their ability to restore cancer cell sensitivity to apoptosis in association with conventional chemotherapeutic drugs, in a large variety of tumors. TRAIL-induced cell death is tightly regulated right from the membrane and at the DISC (Death-Inducing Signaling Complex) level. The following patent and literature chapter is an update to our article “Regulating TRAIL Receptor-Induced Cell Death at the Membrane: A Deadly Discussion”, published in the journal ‘Recent Patents on Anti-Cancer Drug Discovery’, Volume 6, Number 3, September, 2011, Page 311 to 323, reviewing TRAIL DISC components that have been shown to regulate tumor cell fate upon TRAIL engagement.

Inosine monophosphate dehydrogenase (IMPDH), an NAD-dependent enzyme that controls de novo synthesis of guanine nucleotides, has received considerable interest in recent years as an important target enzyme, not only for the discovery of anticancer drugs, but also for antiviral, antiparasitic, and immunosuppressive chemotherapy. The field of IMPDH inhibitor research is highly important for providing potential therapeutics against a validated target for disease intervention. This patent chapter examines the chemical structures and biological activities of recently reported IMPDH inhibitors. Patent databases SciFinder and Espacenet and Delphion were used to locate patent applications that were published between January 2002 and November 2013, claiming chemical structures for use as IMPDH inhibitors. From 2002 to 2014, around 64 primary patent applications have claimed IMPDH inhibitors, which we analyzed by target and applicant. The level of newly published patent applications covering IMPDH inhibitors remains high and a diverse range of scaffolds has been claimed.

Adrenocortical carcinoma (ACC) is a rare neoplasm with very poor prognosis despite the recent development of aggressive antitumor therapies. The cause of adrenal cancer remains elusive, but some molecular mechanisms could be responsible for its development. Target-specific therapies have been developed for a number of human malignancies and have resulted in therapeutic benefits in some cancer patients. However, these therapies are only effective in cases in which the corresponding targets are expressed in tumor tissues. Molecular analysis has had a significant impact on the understanding of the pathogenetic mechanism of ACC development and the evaluation of prognostic and predictive markers, among which alterations of the IGF system, the Wnt pathway, p53 and molecules involved in cancer cell invasion properties and angiogenesis seem to be very promising. These molecular markers may not just play a role in the biology of these tumors and have prognostic implications, but can also be used as potential targets for treatment. The aim of this chapter is to summarize the genetic and molecular events implied in the pathogenesis of ACC and to highlight challenges to the development of anticancer agents in recent patents.

Glioblastoma is the most common, aggressive and lethal brain tumor in adults. However, current therapeutic protocols have low success rates, and average overall survival is less than 15 months. The resistance to therapy is largely a result of the remarkable cellular and phenotypical heterogeneity that characterizes this type of tumor. The discovery of a subpopulation of cells exhibiting stem cell properties within the tumor bulk has profound implications for therapy as increasing evidence indicates that these cells, glioblastoma stem cells (GSCs), are responsible for the origin, maintenance and recurrence of the glioblastomas. These findings highlight the need to characterize GSCs in order to find novel treatments directly targeted specifically against them. In this chapter, we summarize the current knowledge regarding this issue, including some recent and relevant patents.

Proliferation and migration of vascular endothelial cells (ECs) are critical steps in angiogenesis and are strictly controlled by a number extracellular stimula. Proangiogenic peptides binding to tyrosine kinase receptors (i.e. VEGFs and FGFs) are released by several cell types, including ECs and tumor cells. Proangiogenic intracellular signalling cascades involve many messengers working in a sort of network. In particular, in this chapter, we describe the properties and functions of the intracellular calcium signals (Ca_i), a universal, evolutionary conserved and highly versatile pathway involved in the regulation of EC proliferation and migration.

Angiogenic factors generate Ca_i rises via two mechanisms: entry from extracellular medium, through the opening of calcium-permeable channels in the plasmamembrane, or release from intracellular Ca²⁺ stores. Calcium entry, the main topic of this chapter, can be dependent on previously InsP3-activated emptying of calcium stores (storeoperated Ca²⁺ entry - SOCE), or independent on it (non store-operated Ca²⁺ entry - NSOCE). The intracellular pathways underlying endothelial Ca²⁺ entry involve, among the other pathways, arachidonic acid (AA) and nitric oxide (NO) metabolism. Even if some Ca²⁺ entry blockers are under clinical trial with encouraging results, a better knowledge about the molecular nature of proangiogenic Ca²⁺ channels and their intracellular regulation in healthy and pathological processes could lead to new and more powerful strategies in the therapeutical approaches aimed to interfere with altered tissue vascularization. Here, we discuss the state of the art in the field of calcium signaling and angiogenesis, the related recent literature and patents.

Based on the analysis of 303 patents and scientific articles, this state-of-theart review presents Ganoderma lucidum, a medicinal basidiomycete mushroomwithimmunomodulatory and anti-cancer effects. Cultivation methods for the commercial production of Ganoderma lucidum fruit bodies and mycelia are summarized, with main active compounds of triterpenoids, polysaccharides, and proteins, often found in forms of proteoglycans or glycopeptides. Pharmacological effects with emphasis on anti-cancer and immunomodulatory functions are presented, separately for spores and dry mycelia, and for the groups of triterpenoids, polysaccharides, proteins and glycoproteins. Patents disclosing preparation methods of extracts and purified pharmaceutical isolates are reviewed, and examples of anti-cancer formulations, used as pharmaceuticals or nutraceuticals, are given. The chapter suggests that according to the present understanding, the anti-cancer activity ofGanoderma lucidum may be attributed to at least five groups of mechanisms: (1) activation/modulation of the immune response of the host, (2) direct cytotoxicity to cancer cells, (3) inhibition of tumor-induced angiogenesis, (4) inhibition of cancer cells proliferation and invasive metastasis behaviour, and (5) carcinogens deactivation with protection of cells. Although the data from recent in vitro and in vivo studies demonstrate promising anti-cancer effects, a need is identified for further (1) isolation and purification of compounds, with deeper understanding of their individual and synergistic pharmacological effects, (2)molecular level studies of the antitumor and immuno-supportive mechanisms, (3) well designed in vivo tests and controlled clinical studies, and (4) standardisation and quality control for Ganoderma lucidum strains, cultivation processes, extracts and commercial formulations.

Cancer is the second leading cause of death in the Western world. The limited successes of available treatments for cancer means that new strategies need to be developed. The possibility of modifying the cancer cell with the introduction of genetic material opens the way to a new approach based on gene therapy. There are still many technical difficulties to overcome, but recent advances in the molecular and cellular biology of gene transfer have made it likely that gene therapy will soon start to play an increasing role in clinical practice, particularly in the treatment of cancer. Gene therapy will probably be the therapeutic option in cases in which conventional treatments such as surgery, radiotherapy and chemotherapy have failed. The development of modified vectors, and an improved understanding of interactions between the vector and the human host, is generating inventions that are being protected by patents due to the considerable interest of industry for their possible commercialization. We review the latest strategies, patented and/or under clinical trial, in cancer gene therapy. These include patents that cover the use of modified vectors to increase the security and specificity, recombining adenovirus that leads to loss or gain of gene function, activation of the patient's own immune cells to eliminate cancer cells by expression of molecules that enhance immune responses, silencing genes related to the development of drug resistance in patients, inhibition of angiogenesis of solid tumors by targeting the tumor vasculature, and the development of enzymes that destroy viral or cancerous genetic material.

Large-scale (~36,000 atoms) and long-time (30ns each) molecular dynamics (MD) simulations on the complex of imatinib and 16 common mutants of the ABL tyrosine kinase domain have been performed to study the imatinib resistance mechanisms at the atomic level. MD simulations show that longtime computational simulations offer insightful information that static models, simple homology modeling methods, or short-time simulations cannot provide for the BCR-ABL imatinib resistance problem. Three possible types of mutational effects from those mutants are found: the direct effect on the contact interaction with imatinib (e.g. P-loop mutations), the effect on the conformation of a remote region contacting with imatinib (e.g. T315I), and the effect on interaction between two regions within the BCR-ABL domain (e.g. H396P). Contrary to current consensus, insights of novel imatinib resistance mechanisms are revealed and our findings suggest that drugs with different binding modes may be necessary to overcome the drug resistance due to T315I and other mutations. These insights are discussed in light of the recent relevant patent literature.

Cancer is one of the main causes of death in the world and its incidence increases every day. Current treatments are insufficient and present many breaches. Hyperthermia is an old concept and was early established as a cancer treatment option, mainly in superficial cancers. More recently, the concept of intracellular hyperthermia emerged wherein magnetic particles are concentrated at the tumor site and remotely heated using an applied magnetic field to achieve hyperthermic temperatures (42-45ºC). Many patents have been registered in this area since the year 2000. This chapter presents the most relevant information organized in two main categories according to the use or not of nanotechnology. The patents without nanotechnology were divided into the following subcategories: 1) external Radio-Frequency devices; 2) hyperthermic perfusion; 3) frequency enhancers; 4) applying heat to the target site using a catheter; and 5) injection of magnetic and ferroelectric particles. The patents with nanotechnology were divided into three subcategories: 1) hyperthermia devices; 2) nanoparticles; and 3) nanostructures. The use of magnetic nanoparticles is a very promising treatment approach since it may be used for diagnostic and treatment. Magnetic nanoparticle could be applied to detect and diagnose the tumor and to carry a pharmacological active drug to be delivered in the tumor site or apply hyperthermia through an external magnetic field.

Cancer cells and tissues, regardless of their origin and genetic background, have an aberrant regulation of hydrogen ion dynamics leading to a reversal of the intracellular to extracellular pH gradient (ΔpHi to ΔpHe) as compared to normal tissues. This perturbation in pH dynamics occurs very early in carcinogenesis and is one of the most common pathophysiological hallmarks of tumors. Recently, there has been quite a significant increase in our knowledge of the importance and roles of pHi and pHe in developing and driving a series of tumor hallmarks.

This reversed proton gradient is driven by a series of proton export mechanisms that underlie the initiation and progression of the neoplastic process. In this context, one of the primary and best studied regulators of both pHi and pHe in tumors is the Na⁺/H⁺ exchanger isoform 1 (NHE1). The NHE1 is an integral membrane transport protein involved in regulating pH and in tumor cells is a major contributor to the production and maintenance of their reversed proton gradient. It is activated during oncogene-dependent transformation resulting in cytosolic alkalinization which drives subsequent hallmark behaviors including growth factor- and substrate-independent growth, and glycolytic metabolism. It is further activated by various growth factors, hormones, the metabolic microenvironment (low serum, acidic pHe and hypoxia) or by ECM receptor activation.

This chapter will present the recent progress in understanding the role of the NHE1 in determining tumor progression and invadopodia-guided invasion/metastasis and recent patents for NHE1 inhibitors and novel therapeutic protocols for anti-NHE1 pharmacological approaches. These may represent a real possibility to open up new avenues for wide-spread and efficient treatments against cancer.

The antitumour enzyme L-asparaginase (L-Asparagine amidohydrolase, EC 3.5.1.1, ASNase) catalyzes the deamination of L-asparagine to L-Asp and ammonia and has been used for many years in the treatment of acute lymphoblastic leukaemia, Natural Killer cells tumors, subtypes of myeloid leukaemias and T-cell lymphomas. Recently, ovarian carcinomas and other solid tumours have been proposed as additional targets for ASNase, due to its potential role for its glutaminase activity. The increasing attention devoted to the antitumor activity of ASNase prompted us to analyze recent patents specifically concerning this enzyme. An overview of metabolic pathways affected by Asn and Gln depletion along with potential targets of ASNase is discussed. In particular, attention has been paid to novel ASNases, especially the Helicobacter pylori one, and those with amino acid substitutions aimed at improving enzymatic activity of the classical Escherichia coli enzyme. An effort has also been made to include modifications, such as natural glycosylation or synthetic conjugation with other molecules, introduced for therapeutic purposes. Finally, available patent information on biotechnological protocols and strategies applied to production of ASNase as well as to its administration and delivery in organisms has been analyzed.

In this chapter, we discuss the current patents concerning aryl/heteroaryl thiosemicarbazone derivatives as regard to their activities and properties, including coordination (chelation) properties. The mode of action of the aryl/heteroaryl thiosemicarbazone derivatives involves metal coordination with proteins or biological fluids that have metal ions in their structure. Additionally, these molecules can also form multiple hydrogen bonds through their (thio) amide and N3 nitrogen that ensure a strong interaction with the receptor. In some cases, strong π-π interactions can be observed between the aryl/heteroaryl rings and the tyrosine or other aromatic amino acids. Special attention is given to pyridyl, bis-pyridyl, benzoylpyridyl and isatin thiosemicarbazone derivatives that exhibit significant anticancer, antiviral and other activities in free and in metal complex forms. This key biological role is often related with their capability to inhibit the enzyme ribonucleotide reductase, similar to what is observed with potent anticancer drugs such as Triapine ((3-aminopyridine-2- carboxaldehyde thiosemicarbazone) (3-AP)) and methisazone. Recent studies have revealed that thiosemicarbazone can also inhibit topoisomerase IIα enzyme. Thiosemicarbazone derivatives form coordination complex with various metals such as Zn, Cu, Fe, Co, Ni, Pt, Pd, etc, and these complexes provide better activities than the free thiosemicarbazones. Recent patents show that the controlled or sustained release dosage form of the thiosemicarbazone derivatives along with ionizing radiations is used for the treatment of proliferative diseases (US20110152281, US20110245304, US20120172217, WO2012079128 and WO2013082661).

The chapter is dedicated to the issues of clinical oncoproteomics, its role and place in contemporary medicine in general, and in oncology in particular. We attempted to systemize the views of different researchers and detect information and significance of the evidence of clinical oncoproteomics for the development of novel methods of diagnostics and cancer therapy using cell, genome and post-genome technologies. The chapter summarizes contemporary ideas of tumor carcinogenesis centrally laying emphasis on the theoretical, methodological and technic the aspects of the novel medical approach of personalized proteome-based cell therapy of neoplasms. Experience of mapping, proteome and transcriptome profiling of postnatal regional progenitors and cancer stem cells in different cancer cases, methods of bioinformatical processing and mathematical modeling of the results have been elucidated. The basic mathematical tool kit to detect targets for the regulation of proliferative and reproductive functions of cancer stem cell in the tumor and the way to obtain target individually tailored anti-cancer proteome-modified cell preparations have been highlighted. Further, the mechanisms, limitations and prospects of application of these biotechnologies based on clinical oncoproteomics in the target therapy of cancer and recent patents have also been discussed.

Some growth hormone-releasing hormone (GHRH) antagonists are able to inhibit the growth of various experimental human cancers. The antitumor effects of first antagonists seemed to be dependent mainly on the disruption of pituitary secretion of growth hormone (GH), followed by a reduction in the levels of circulating insulin-like growth factor (IGF)-1, an important growth factor for cancer cells. It seems obvious that growth hormone deficiency (GHD) induced by GHRH antagonists, with all its complications, could limit the beneficial effects of GHRH antagonist therapy, and decrease the quality of life of the patient. The discovery of local autocrine/paracrine production of GHRH and other related growth factors in many tumoral tissues, together with that of the wide expression of GHRH receptors on cancer cells, have directed research to the synthesis of more potent GHRH antagonists. These compounds exert strong inhibitory effects directly on tumor growth, with scarce endocrine action. The receptor-mediated mechanisms are complex and still not completely understood, and involve various intracellular signaling pathways strictly related to human tumorigenesis. This chapter summarizes the recent patents and latest observations on the antineoplastic role of GHRH antagonists in human tumors with an emphasis on the potential therapeutic applications for clinical oncology.

A major challenge in cancer research is the discovery of drugs with high selectivity and only minor side effects. Tamoxifen has been widely used for more than 30 years in breast cancer treatment and prevention, and it acts primarily via oestrogen receptors (ERs). However, it also displays anti-tumour activity in ER-negative breast cancer, suggesting that tamoxifen targets other proteins. Indeed, tamoxifen has effects on several signal transduction pathways and ion channels, which are involved in tumor progression; these targets of tamoxifen with antitumor potential can be targeted in the search for more effective drugs. Despite the successful use of tamoxifen, it produces some undesirable side effects by acting on different targets, many of which have not been clarified. Thus, several strategies have been proposed to increase the effectiveness of tamoxifen. These strategies include the synthesis of compounds with chemical structures analogous to tamoxifen as well as different routes of administration for this group of compounds and the use of tamoxifen in combination with other antineoplastic drugs. This chapter will first briefly describe the current and general aspects of tamoxifen and will then focus more in depth on various patented analogues, patented uses of tamoxifen, and patented combinations of tamoxifen with other antineoplastic drugs. We also discuss the biological effects of tamoxifen and its therapeutic targets. This chapter provides an updated look at current tamoxifen-based therapies and new strategies for using tamoxifen to benefit cancer patients.

Telomerase, a specialised RNA-directed DNA polymerase extends and stabilises the telomeres at the ends of the eukaryotic chromosomes. The progressive loss of telomeres results in limited number of cell divisions and has been linked to the mechanism of human cellular ageing. Tumor cells marked by indefinite proliferation have stable telomere length maintained by telomerase. The differential expression of the telomerase enzyme in normal and cancer cells has led to the evolution of tumor specific anti-telomerase approaches which inhibit the telomerase enzyme activity so as to destabilise and shorten the telomeres leading to senescence in cancer cells.

In the current chapter, we have selected nine tumor specific anti-telomerase approaches based on their mechanism of action or the target components of the human telomerase enzyme: Antisense-oligonucleotides, hammerhead ribozymes, dominant negative human telomerase reverse transcriptase (DN- hTERT), reverse-transcriptase inhibitors, immunotherapy, G-quadruplex stabilisers, gene therapy, small molecule inhibitors and RNA interference. Recent research developments for each of the anti-telomerase approaches with the detailed analysis of specific granted patents from the perspective of different claims and downstream applications have been provided. A comprehensive list of patents for the different anti-telomerase approaches which includes information regarding the authors and institutional ownership along with the year of issue of the patent has also been provided. The chapter also presents a perspective on nanotechnology based delivery of anti- telomerase cancer therapeutics.