Current Medicinal Chemistry (v.19, #22)

The early detection of urological cancers is pivotal for successful patient treatment and management. The development of molecular assays that can diagnose disease accurately, or that can augment current methods of evaluation, would be a significant advance. Ideally, such molecular assays would be applicable to non-invasively obtained body fluids, enabling not only diagnosis of at risk patients, but also asymptomatic screening, monitoring disease recurrence and response to treatment. The advent of advanced proteomics and genomics technologies and associated bioinformatics development is bringing these goals into focus. In this article we will discuss the promise of biomarkers in urinalysis for the detection and clinical evaluation of the major urological cancers, including bladder, kidney and prostate. The development of urine-based tests to detect urological cancers would be of tremendous benefit to both patients and the healthcare system.

Prophylactic Vaccine Approach for Colon and Pancreatic Cancers: Present and Future by N. B. Janakiram, A. Mohammed, M. S. Bronze, C. V. Rao (3664-3678).
Vaccines against cancers have not been as effective as vaccines against infectious diseases. However, recent studies have advanced our understanding of the stages of tumor cell development and of mechanisms of immune surveillance, immune suppression, and of tumor escape from the immune system. The development of animal models that mimic development of human cancers has helped advance the understanding of these processes and is aiding the development of greatly improved vaccines. Here we review the recent progress in developing vaccines and prophylactic approaches for pancreatic and colon cancers. Improved understanding of the expression of various oncogenes and tumor-associated antigens helps in selecting antigenic targets for stage-specific immune prevention. Identification of the earliest alterations in precancerous lesions and selection of epitopes unique to the aberrant cells and capable of triggering strong cytotoxic and helper T cell responses may aid the development of safe and effective vaccines for use in those at high risk of progressing to invasive cancers. The responses can be enhanced with carefully selected adjuvants to boost immunity and by selecting epitopes that are expressed on dendritic cells, thereby promoting T cell responses. Tumor resistance via loss of the targeted antigen can be mitigated by inclusion of multiple tumor epitopes in vaccine constructs. Tumor immune escape can be diminished by targeting various immunosuppressive mechanisms used by different tumors, such as tumor production of immunosuppressive cytokines (e.g., interleukin 10, and Transforming Growth Factor-beta, which can promote activity of immunosuppressive regulatory T cells), or by inhibiting production of inflammatory prostanoids with combined cyclooxygenase/lipoxygenase inhibitors. Finally, prevention of many cancers may be enhanced by carefully selecting and scheduling of vaccine administration in combination with other chemotherapeutic or chemopreventive agents. Preclinical and early clinical trials incorporating these principles are discussed.

Survivin as a Prognostic/Predictive Marker and Molecular Target in Cancer Therapy by F. Rodel, T. Sprenger, B. Kaina, T. Liersch, C. Rodel, S. Fulda, S. Hehlgans (3679-3688).
Evasion from apoptotic cell death is reported to be a pivotal mechanism by which tumor cells acquire resistance to therapeutic treatment. Targeting the apoptotic pathways may constitute a promising strategy to counteract therapy resistance and to re-sensitize cancer cells. Expression of survivin, the smallest and structurally unique member of the inhibitor of apoptosis protein (IAP) family, has been shown to be associated with poor clinical outcome, more aggressive clinicopathologic features and resistance to both, conventional chemo and radiation therapy. Moreover, survivin detection in cancer tissue, in circulating tumor cells and in patient’s serum has prognostic and predictive relevance and may display a prerequisite for marker based molecular therapies. Indeed, due to its universal over expression in malignant tissue, and its prominent role at disparate networks of cellular division, intracellular signaling, apoptosis and adaption to unfavorable surroundings, survivin has been shown to be a suitable target for a targeted therapy. The applicability of survivindriven strategies in clinical practice is currently under investigation as the first survivin antagonists (small molecule inhibitors, antisense oligonucleotides and immunotherapy) successfully entered phase I/II trials. Taken together, these data provide a rationale for the implementation of both, survivin as a molecular diagnostic tool and survivin targeted therapies, within future clinical practice.

Molecular and Clinical Analysis of Predictive Biomarkers in Non-Small-Cell Lung Cancer by A. Passaro, A. Palazzo, P. Trenta, M. L. Mancini, F. Morano, E. Cortesi (3689-3700).
Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-specific death in the USA and Europe. Over the last two decades, the pathogenetic mechanisms and the molecular alterations of NSCLC have been investigated more intensively, a number of potential therapeutic targets have been identified and new agents against specific molecular targets have been introduced in the treatment of NSCLC. Acquired abnormalities in the genes encoding RAS, p53, KRAS, EGFR and ALK, are particularly important in this field. Whenever targetable mutations are not found, the research of other genetic abnormalities can be useful to personalize chemotherapy. The attention has been focused, in particular, on the endonuclease excision repair cross-complementing1 and BRCA1 status. The use of antimetabolite drugs and the level of expression of their cellular targets seem to be correlated and influence the clinical efficacy of those agents. This review will focus on the role of predictive biomarkers for the treatment of non-small cell lung cancer.

Early Detection and Prevention of Pancreatic Cancer: Use of Genetically Engineered Mouse Models and advanced Imaging Technologies by A. Mohammed, N. B. Janakiram, S. Lightfoot, H. Gali, A. Vibhudutta, C. V. Rao (3701-3713).
Lack of early detection and effective interventions are major factors contributing to the poor prognosis and dismal survival rates of pancreatic cancer patients for more than sixty years. Detection of pancreatic cancer at an early stage might permit life-saving intervention. Clinical and preclinical diagnosis and evaluation of pancreatic cancers involve several imaging technologies including magnetic resonance imaging (MRI), Positron emission tomography (PET), Computed tomography (CT), Ultrasound (US), bioluminescent imaging and single photon emission computed tomography (SPECT). The advent of genetically engineered animal models that recapitulate the cellular and molecular pathology of human pancreatic intraepithelial neoplasia (PanINs) and pancreatic ductal adenocarcinoma (PDAC) has not yet yielded translational implications. Although the use of tumor xenografts to predict drug efficacy in patients has been disappointing, use of novel transgenic mice models should permit improved early detection and development of drug regimens through integration of appropriate imaging modalities. This review will consider issues that are unique to working with transgenic mouse models, such as the biology of genetically engineered mouse (GEM) models, stage- tumor-specific detection using imaging technologies, use of monoclonal antibodies, nanoparticles, and biomarkers, and development of chemopreventive and chemotherapeutic drugs for PDAC. These issues will be considered in the context of recently developed preclinical models of pancreatic cancer.

Combinatorial Nanoparticles for Cancer Diagnosis and Therapy by A. Mukerjee, A. P. Ranjan, J. K. Vishwanatha (3714-3721).
Nanotechnology when engineered together with biotechnology opens a fascinating field with applications in diverse areas such as drug targeting and delivery, medical imaging, biosensing, biomaterials and nanotechnology. Conjugating nanoparticles with biomolecules like QD-herceptin conjugates or QD-aptamer (Apt)-DOX conjugates provides many opportunities for improving many of the current challenges in cancer diagnosis and therapy. This paper reviews combinatorial nanoparticles designed and formulated for cancer imaging and therapy, including inorganic nanoparticles (quantum dots, iron oxide particles, gold nanoparticles and silica and carbon nanoparticles), polymeric nanoparticles (PLGA, PLGA-PEG, PAMAM), liposomes and lipid nanoparticles. These nanoparticles are multifunctional in nature and combine two or more functions like targeting, imaging and therapy. In this review, we have classified these combinatorial targeted nanoparticles into inorganic, polymeric and liposome based nanosystems.

The increasing incidence of hepatocellular carcinoma (HCC) is of great concern not only in the United States but throughout the world because of two major reasons: firstly, HCC is one of the most lethal form of malignancies with less than 10% survival rate and secondly, a lack of prudent diagnostics makes early detection of HCC nearly impossible. The poor prognosis of HCC accentuates the need to develop new diagnostic markers and therapeutic approaches. In this review we discuss recent advances made in the discovery of molecular biomarkers and their significance in the detection of HCC. We focus on three major classes of biomarkers: serological, tumor, peri-tumoral tissue and cancer stem cell markers. Considerable progress has been made recently in our understanding of HCC at the molecular level increasing the potential of molecular targeted therapy. A number of molecular targets have been identified that have been showing promising results. Of particular interest is Sorafenib, a multi-tyrosine kinase inhibitor that has been approved for the HCC treatment. Inhibitors of other molecular targets such as VEGF, EGFR, mTOR etc. are emerging as plausible therapeutic agents for the treatment of HCC and are discussed in this review.

In-Situ Hybridization as a Molecular Tool in Cancer Diagnosis and Treatment by Z. Jehan, S. Uddin, K. S. Al-Kuraya (3730-3738).
In situ hybridization (ISH) is a type of hybridization that uses a labeled complementary DNA or RNA strand to localize a specific DNA or RNA sequence on a chromosome or section of tissue (in-situ) fixed on a slide. Flourescence in-situ hybridization (FISH) technique facilitates the localization of genes to different chromosomal locations. It is extensively applied as a gene mapping tool for identification and validation of cytogenetic aberrations identified through comparative genomic hybridization (CGH) on large cohort of archival samples in a tissue microarray format. The discovery of cytogenetic aberrations in cancer has led to the development of quite a few FDA approved molecularly targeted drugs for the management of patients undergoing cancer treatment. FISH technique is extensively utilized as a predictor of responsiveness to treatment with targeted inhibitors, residual disease monitoring and also in noninvasive methods for the detection of tumor cells. Furthermore detection of circulating tumor cells can be detected which have metastatic potential with poor survival prospects. With the development of high throughput technologies like comparative genomic hybridization CGH and next-generation DNA sequencing, human pathology archival specimens of human tumors in various stages of development, can be utilized in the post-human-genome-sequencing era to obtain diagnostic and therapeutic guidance. This article will discuss the extensive application of FISH in diagnosis, prognosis and therapeutic monitoring of cancer.

Genetic information is an extremely valuable data source in characterizing the personal nature of cancer. Chromosome instability is a hallmark of most cancer cells. Chromosomal abnormalities are correlated with poor prognosis, disease classification, risk stratification, and treatment selection. Copy number alterations (CNAs) are an important molecular signature in cancer initiation, development, and progression. Recent application of whole-genome tools to characterize normal and cancer genomes provides the powerful molecular cytogenetic means to enumerate the multiple somatic, genetic and epigenetic alterations that occur in cancer. Combined array comparative genomic hybridization (aCGH) with single nucleotide polymorphism (SNP) array is a useful technique allowing detection of CNAs and loss of heterozygosity (LOH) or uni-parental disomy (UPD) together in a single experiment. It also provides allelic information on deletions, duplications, and amplifications. UPD can result in an abnormal phenotype when the chromosomes involved are imprinted. Myelodysplastic syndromes (MDS) are the most common clonal stem cell hematologic malignancy characterized by ineffective hematopoiesis, which leads to rapid progression into acute myeloid leukemia. UPD that occurs without concurrent changes in the gene copy number is a common chromosomal defect in hematologic malignancies, especially in MDS. Approximately 40-50% of MDS patients do not have karyotypic abnormalities that are detectable using classical metaphase cytogenetic techniques (MC) because of inherent limitations of MC, low resolution and the requirement of having dividing cells. In this review, we highlight advances in the clinical application of microarray technology in MDS and discuss the clinical potential of microarray.

The AKT family of serine threonine kinases is of critical importance with regard to growth factor signaling, cell proliferation, survival and oncogenesis. Engagement of signaling receptors induces the lipid kinase, phosphatidylinositol 3-kinase (PI3K), which enables the activation of AKT. Responsive to the PI3K/AKT pathway is the mammalian target of rapamycin (mTOR), a major effector that is specifically implicated in the regulation of cell growth as a result of nutrient availability and cellular bioenergetics. These kinases mediate the activity of a multitude of intracellular signaling molecules and intersect with multiple pathways that regulate cellular processes. Elucidating the role of AKT/mTOR in metabolism and in hallmark signaling pathways that are aberrantly affected in cancer has provided a solid foundation of discoveries. From this, new research directions are emerging with regard to the role of AKT/mTOR in diabetes and T cell-mediated immunity. As a result, a new perspective is developing in how AKT/mTOR functions within intracellular signaling pathways to maintain cellular homeostasis. An appreciation is emerging that altered equilibrium of AKT/mTOR pathways contributes to disease and malignancy. Such new insights may lead to novel intervention strategies that may be useful to reprogram or reset the balance of intracellular signaling.

Structure and Ligand Based Drug Design Strategies in the Development of Novel 5- LOX Inhibitors by Polamarasetty Aparoy, Kakularam Kumar Reddy, Pallu Reddanna (3763-3778).
Lipoxygenases (LOXs) are non-heme iron containing dioxygenases involved in the oxygenation of polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA). Depending on the position of insertion of oxygen, LOXs are classified into 5-, 8-, 9-, 12- and 15-LOX. Among these, 5-LOX is the most predominant isoform associated with the formation of 5-hydroperoxyeicosatetraenoic acid (5- HpETE), the precursor of non-peptido (LTB4) and peptido (LTC4, LTD4, and LTE4) leukotrienes. LTs are involved in inflammatory and allergic diseases like asthma, ulcerative colitis, rhinitis and also in cancer. Consequently 5-LOX has become target for the development of therapeutic molecules for treatment of various inflammatory disorders. Zileuton is one such inhibitor of 5-LOX approved for the treatment of asthma. In the recent times, computer aided drug design (CADD) strategies have been applied successfully in drug development processes. A comprehensive review on structure based drug design strategies in the development of novel 5-LOX inhibitors is presented in this article. Since the crystal structure of 5-LOX has been recently solved, efforts to develop 5-LOX inhibitors have mostly relied on ligand based rational approaches. The present review provides a comprehensive survey on these strategies in the development of 5-LOX inhibitors.

Expression of Specificity Protein Transcription Factors in Pancreatic Cancer and their Association in Prognosis and Therapy by Umesh T. Sankpal, Pius Maliakal, Debashish Bose, Omar Kayaleh, Daniel Buchholz, Riyaz Basha (3779-3786).
Pancreatic cancer is an aggressive malignancy with poor prognosis. Pancreatic adenocarcinoma is one of the leading causes of cancer-related deaths in the United States. Due to the aggressive nature of this malignancy, there is a serious concern for identifying effective targets, and adopting novel strategies for therapy. Members of the Specificity Protein (Sp) family of transcription factors, Sp1, Sp3, and Sp4 regulate the expression of a number of genes associated with cancer cell proliferation, differentiation, and metastasis. Sp1 levels are upregulated in pancreatic cancer cell lines, and surgically resected human pancreatic adenocarcinoma. Sp1 overexpression in tumor tissues is associated with aggressive disease, poor prognosis and inversely correlated with survival. Sp1 is also known to affect angiogenesis by regulating the expression of vascular endothelial growth factor and its receptors. Results from clinical studies suggest Sp1 as new biomarker to identify aggressive pancreatic ductal adenocarcinoma. The pharmacological inhibition of Sp1 using agents such as celecoxib, mithramycin, curcumin, and tolfenamic acid has showed promising results in pre-clinical studies and demonstrated Sp transcription factors as potential targets for pancreatic cancer therapy. This review summarizes studies showing the association of Sp proteins with this malignancy, with a special emphasis on pre-clinical studies that tested strategies to target Sp transcription factors for inhibiting human pancreatic cancer cell proliferation and tumor growth in laboratory animals. The results showed remarkable efficacy and suggest that such approaches have the potential for high success in developing clinically relevant strategies for treating pancreatic cancer.

Cellular Therapy for Ovarian Cancer: Experimental and Clinical Perspectives by Susan B. Ingersoll, Sarfraz Ahmad, Neil J. Finkler, John R. Edwards, Robert W. Holloway (3787-3793).
Ovarian cancer is the leading cause of death among gynecologic malignancies and the 5th leading cause of cancer deaths for women in the United States. Two-thirds of patients present with advanced-stage disease (Stage III and IV) and the majority will suffer recurrence of disease, require ongoing treatment, and eventually succumb to chemotherapy-resistant disease. To potentially circumvent chemo-resistance in recurrent ovarian cancer, immunotherapy is being explored as a novel treatment option. Our laboratory findings demonstrate that immune effector cells from healthy donors elicit a significant cytotoxic response in the presence of IL-2 and IFN alpha- 2b against ovarian cancer in vitro; however, peripheral blood mononuclear cells (PBMC) isolated from ovarian cancer patients fail to elicit a similar response. A major obstacle to immunotherapy is the immunosuppressive environment supported by tumors, which limits the immune system’s ability to fight the tumor. Myeloid-derived suppressor cells are an immature population of myeloid cells, which have recently been implicated to play a major role in immunosuppression and tumor evasion. In addition to novel immunotherapies, new diagnostic and prognostic markers are being identified through applying molecular tools/approaches in clinical and pathological analyses of this malignancy, which will provide additional therapeutic targets. To test these experimental therapeutic options, pre-clinical murine models of ovarian cancer are being developed. Ultimately, treatment of ovarian cancer will benefit from the careful alignment of appropriate target, drug, patient, and trial design. This article provides an objective overview of cellular therapy (the use of immune cells to elicit an anti-tumor response) for ovarian cancer highlighting both experimental and clinical perspectives.

The Use of Therapeutic Peptides to Target and to Kill Cancer Cells by R. J. Boohaker, M. W. Lee, P. Vishnubhotla, J. L. M. Perez, A. R. Khaled (3794-3804).
Peptide therapeutics is a promising field for emerging anti-cancer agents. Benefits include the ease and rapid synthesis of peptides and capacity for modifications. An existing and vast knowledge base of protein structure and function can be exploited for novel peptide design. Current research focuses on developing peptides that can (1) serve as tumor targeting moieties and (2) permeabilize membranes with cytotoxic consequences. A survey of recent findings reveals significant trends. Amphiphilic peptides with clusters of hydrophobic and cationic residues are features of anti-microbial peptides that confer the ability to eradicate microbes and show considerable anti-cancer toxicity. Peptides that assemble and form pores can disrupt cell or organelle membranes and cause apoptotic or necrotic death. Cell permeable and tumor-homing peptides can carry biologically active cargo to tumors or tumor vasculature. The challenge lies in developing the clinical application of therapeutic peptides. Improving delivery to tumors, minimizing non-specific toxic effects and discerning pharmacokinetic properties are high among the needs to produce a powerful therapeutic peptide for cancer treatment.

Melatonin, A Natural Programmed Cell Death Inducer in Cancer by M. Sanchez-Hidalgo, J. M. Guerrero, I. Villegas, G. Packham, C. A. de la Lastra (3805-3821).
Melatonin, an indolamine derived from the amino-acid tryptophan, participates in diverse physiological functions and has great functional versatility related to the regulation of circadian rhythms and seasonal behaviour, sexual development, retinal physiology, tumour inhibition, as an antioxidant, immunomodulatory and anti-aging properties. In relation to its oncostatic properties, there is evidence that tumor initiation, promotion or progression may be restrained by the night-time physiological surge of melatonin in the blood or extracellular fluid. In addition, depressed nocturnal melatonin concentrations or nocturnal excretion of the main melatonin metabolite, 6-sulfatoxymelatonin, were found in individuals with various tumor types. In the majority of studies, melatonin was shown to inhibit development and/or growth of various experimental animal tumors and some human cell lines in vitro. Many tumors do not respond to drug treatment due to their resistance to undergo apoptosis thereby contributing to the development of cancer. Thus, given the importance of the apoptotic program in cancer treatment, the role of melatonin in influencing apoptosis in tumor cells attracted attention because it seems that it actually promotes apoptosis in most tumor cells, in contrast to the obvious inhibition of apoptotic processes in normal cells. Thus, this paper is also intended to provide to the reader an up-date of all the researches that have been carried out to date, which investigate the proapoptotic effects of melatonin in experimental preclinical models of cancer (in vitro and in vivo) and the underlying proposed action mechanism of this effects. If melatonin uniformly induces apoptosis in cancer cells, the findings could have important clinical implications to improve the quality of live while preventing the appearance of cancer.

The role of natural products as a source for remedies has been recognized since ancient times. Despite major scientific and technological progress in combinatorial chemistry, drugs derived from natural product still make an enormous contribution to drug discovery today. Nature is an attractive source of new therapeutic candidate compounds since a tremendous chemical diversity is found in millions of species of plants, animals, marine organisms and microorganisms. Microorganisms such as bacteria and fungi have been invaluable to discover drugs and lead compounds. These microorganisms produce a large variety of antimicrobial agents which have evolved to give their hosts an advantage over their competitors in the microbiological world. The screening of microorganisms became highly popular after the discovery of penicillin but in recent years the list of antibacterial agents (bacteria- or fungi-derived) has increased considerably with the arrival of cephalosporins, tetracyclines, aminoglycosides, rifamycins, and chloramphenicol. Although most of the drugs derived from microorganisms are used in antibacterial therapy, some microbial metabolites have provided lead compounds in other fields of medicine. For example: the fungal metabolite lovastatin, which was the lead compound for a series of drugs that lower cholesterol levels, the ciclosporin (fungal metabolite) currently used to suppress the immune response after transplantation operations and sirolimus- a bacterium-derived macrolide- used in the treatment of some cancers. The aim of this review is to analyze the current uses and the future applications in therapeutic treatments of microorganism-derived products (MdPs) and discuss the results obtained in the some clinical trials.

Approaches to Target Profiling of Natural Products by R. Yue, L. Shan, X. Yang, W. Zhang (3841-3855).
Natural products have long been regarded as excellent sources for drug discovery given their structural diversity and wide variety of biological activities. Accordingly, the identification of the molecular targets of natural products is an important aspect of current drug discovery, as knowledge regarding a compound's molecular targets will greatly aid drug development and design. In this review, we will explore genomic, proteomic, and computational approaches to the elucidation of these mechanisms and the implications of these approaches for the target profiling of natural products. The recent applications of target profiling of natural products will also be reviewed.