Forum on Immunopathological Diseases and Therapeutics

Published by Begell House
Online ISSN: 2151-8017
Publications
Article
Promising drug candidates of the diazeniumdiolate (NONOate) chemical family include several types of thiol modification among their mechanisms of action: 1) drugs designed to release nitric oxide (NO) on reaction with the thiol group of glutathione (GSH) arylate the GSH, a step that removes reducing equivalents from the cell; (2) a similar reaction of the drug with the thiol group of a protein changes its structure, leading to potentially impaired function and cell death; (3) the NO generated as a byproduct in the above reactions can undergo oxidation, leading to S-nitrosylation and S-glutathionylation; and (4) diazeniumdiolates can also generate nitroxyl, which reacts with thiol groups to form disulfides or sulfinamides.
 
Article
Phosphatidylethanolamine-binding protein (PEBP) was identified almost three decades ago as an abundant protein in bovine brain. PEBP is the prototype of a highly conserved family of proteins represented in all three major phylogenetic divisions, eukaryota, bacteria, and archaea, with no significant sequence homology to other proteins. PEBP proteins have been studied in many species. The most thoroughly explored biological role of PEBP is that of a modulator of intracellular signaling pathways, which is mediated by its ability to bind and inhibit a number of protein kinases. The first such interaction that came to light was with the Raf1 kinase, and PEBP is thus widely referred to in the literature under its alternate name RKIP (Raf kinase inhibitory protein). The activity of RKIP itself is subject to regulation by phosphorylation. Intriguingly, PEBP has also been reported to possess additional, and diverse, biological functions unrelated to protein kinase networks that remain to be investigated in detail. Recent findings that RKIP may function as a suppressor of cancer metastasis are of great interest and importance. Prognostic and therapeutic applications of RKIP in human cancer were the subject of the first international workshop on RKIP that was held at the University of California, Los Angeles, in March 2010. This paper was presented at the workshop as a summary of the history of this still small but rapidly evolving field.
 
Article
Nitric oxide (NO) has been widely recognized as an important cell-signaling molecule that regulates various physiological and pathological processes. S-nitrosylation, or covalent attachment of NO to protein sulfhydryl groups, is a key mechanism by which NO regulates protein functions and cellular processes. In this article we discuss the various roles of NO and protein nitrosylation in cancer development, with a focus on cell invasion and anoikis resistance, both of which are key determinants of cancer metastasis. We specially address some of the mechanisms by which NO-mediated S-nitrosylation modulates substrates that have putative effects on key steps of metastasis. We propose that nitrosothiol signaling is a key regulatory mechanism common to several pathways involved in cancer progression and metastasis, and identifying such a mechanism will improve our understanding of the disease process and aid in the development of novel anticancer therapeutics.
 
Article
O(2)-(2,4-Dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K) and O(2)-{2,4-dinitro-5-[4-(N-methylamino)be nzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate (PABA/NO) are O(2)-arylated diazeniumdiolates that have shown promising in vivo activity in a variety of rodent cancer models, including prostate cancer, leukemia, liver cancer, multiple myeloma, and ovarian cancer. This compound class was designed to be activated for anti-cancer effects by glutathione-S-transferase (GST)-induced release of cytotoxic nitric oxide (NO), but mechanistic studies have implicated a variety of pathways, some GST/NO-related, some not. Current work is focused on improving formulations and other drug development activities, as well as exploring possible new applications of these agents and their analogs. The selectivity of these drugs for attacking tumors while exhibiting little toxicity toward normal tissues suggests considerable promise for the treatment of various tumor types.
 
This schematic diagram represents the constitutively activated and deregulated NF- k B/Snail/YY1/RKIP loop in cancer cells. The black solid lines demonstrate that activated NF- k B regulates the transcription and expression of Snail. Snail is a transcription repressor of RKIP and, therefore, there is minimal suppression of NF- k B by RKIP. In addition, NF- k B activates the transcription and expression of YY1. YY1 has been shown to positively regulate the transcription and expression of Snail. Therefore, the activation of NF- k B, Snail, and YY1 along with the inactivation of RKIP results in the regulation of tumor cells’ chemo-immuno-resistance to cytotoxic agents. However, inhibitors of the loop shown here (red solid lines), such as inhibitors of NF- k B (by chemicals, proteasome inhibitors, NO, etc.) result downstream in the inhibition of Snail and YY1 along with the induction of RKIP. Like the inhibition of NF- k B, the direct inhibition of Snail or YY1 (by shRNA, inhibitors, etc.) will also result in the induction of RKIP and further inhibiting the NF- k B/YY1/Snail circuit. Altogether, the various inhibitors will result in the reversal of tumor cells’ chemo- immuno-resistance to chemo-immuno-sensitivity to cytotoxic agents. 
Article
The current anti-cancer therapeutic armamentarium consists of surgery, chemotherapy, radiation, hormonal therapy, immunotherapy, and combinations thereof. Initial treatments usually result in objective clinical responses with prolongation of overall survival (OS) and progression-free survival (PFS) in a large subset of the treated patients. However, at the onset, there is a subset of patients who does not respond and another subset that initially responded but experiences relapses and recurrences. These latter subsets of patients develop a state of cross-resistance to a variety of unrelated therapies. Therefore, there is an urgent need to first unravel the underlying mechanisms of resistance and associated gene products that regulate the cross-resistance. Such gene products are potential therapeutic targets as well as potential prognostic/diagnostic biomarkers. In this context, we have identified three interrelated gene products involved in resistance, namely, Snail, YY1, and RKIP that are components of the dysregulated NF-κB/Snail/YY1/RKIP loop in many cancers. In this review, we will discuss the roles each of Snail, YY1 and RKIP in the regulation of tumor cell resistance to chemo and immunotherapies. Since these same gene products have also been shown to be involved in the regulation of the EMT phenotype and metastasis, we suggest that targeting any of these three gene products can simultaneously inhibit tumor cell resistance and metastasis.
 
Article
NF-κB has long been known to play an important role in autoimmune diseases such as rheumatoid arthritis (RA). Indeed, as our understanding of how NF-κB is utilized has increased, we have been hard put to find a process not associated with this transcription factor family in some way. However, new data originating, in part, from genome-wide association studies have demonstrated that very specific alterations in components of the NF-κB pathway are sufficient to confer increased risk of developing disease. Here we review the data which have identified specific components of the NF-κB pathway, and consider what is known of their mechanisms of action and how these mechanisms might play into the disease process. In addition, the use of genetic information to predict RA is considered.
 
Article
Raf kinase inhibitor protein (RKIP) interacts with a number of different proteins and regulates multiple signaling pathways. Here, we show that locostatin, a small molecule that covalently binds RKIP, not only disrupts interactions of RKIP with Raf-1 kinase, but also with G protein-coupled receptor kinase 2. In contrast, we found that locostatin does not disrupt binding of RKIP to two other proteins: inhibitor of κB kinase α and transforming growth factor β-activated kinase 1. These results thus imply that different proteins interact with different regions of RKIP. Locostatin's mechanism of action involves modification of a nucleophilic residue on RKIP. We observed that after binding RKIP, part of locostatin is slowly hydrolyzed, leaving a smaller RKIP-butyrate adduct. We identified the residue alkylated by locostatin as His86, a highly conserved residue in RKIP's ligand-binding pocket. Computational modeling of the binding of locostatin to RKIP suggested that the recognition interaction between small molecule and protein ensures that locostatin's electrophilic site is poised to react with His86. Furthermore, binding of locostatin would sterically hinder binding of other ligands in the pocket. These data provide a basis for understanding how locostatin disrupts particular interactions of RKIP with RKIP-binding proteins and demonstrate its utility as a probe of specific RKIP interactions and functions.
 
Article
Chronic inflammation within the tumor microenvironment is a major driver of tumor progression and poor prognosis. Inducible nitric oxide synthase (NOS2) is present in numerous solid tumors. Estrogen receptor-negative (ER-) patients with high expression of tumor NOS2 have a poorer outcome than patients with low expression of NOS2. Furthermore, expression of NOS2 is associated with the basal-like breast cancer phenotype. Using an in vitro model, we have found that nitrosation of critical thiols and nitration of tyrosines lead to the activation of membrane receptors such as epithelial growth factor receptor, Src, Ras, and CD63. These nitric oxide-mediated events in itiate oncogenic signaling pathways such as PI3K/Akt, Ras/ERK, β-catenin, nuclear factor-κB, and AP-1. These data suggest that NOS2 can serve as a major "nonmutatational driver" of ER- breast cancer.
 
Article
Treatment of cancer cell lines with high levels of nitric oxide (NO) via NO donors, such as DETANONOate, inhibits cell growth and survival pathways and sensitizes resistant tumor cells to apoptosis by chemoimmunotherapeutic drugs. In addition, we recently have reported that NO also inhibits the epithelial-to-mesenchymal transition (EMT) phenotype in metastatic cancer cell lines via dysregulation of the nuclear factor (NF)-κB/Snail/Yin Yang 1 (YY1)/Raf kinase inhibitor protein circuitry. The mechanism underlying NO-mediated dysregulation of this circuit was investigated, namely, NO-mediated inhibition of the activity of the transcription factors NF-κB, Snail, and YY1. We hypothesized that one mechanism of NO-mediated inhibition may invoke the NO-induced S-nitrosylation of these transcription factors. We demonstrate in metastatic and EMT(+) human prostate carcinoma cell lines that treatment with NO results in the S-nitrosylation of NF-κB (p50), Snail, and YY1 and inhibits their activities, resulting in the reversal of the EMT phenotype into a mesenchymal-to-epithelial transition phenotype. These findings suggest that NO donors may be potential therapeutic agents in both the reversal of resistance and the inhibition of EMT and metastasis.
 
Article
Raf kinase inhibitor protein (RKIP) is a small, cytosolic protein named for its ability to block Raf-mediated activation of MAPK and ERK. It also block G-protein signaling and NF-κB activation. An in vitro screen to identify genes that regulate prostate cancer (PCa) metastasis revealed that expression of RKIP was decreased in high versus low metastatic PCa cells. Modulation of RKIP expression revealed that it inhibited invasion and loss of RKIP promoted in vitro invasion. Animal studies were used to demonstrate that RKIP could inhibit PCa metastasis from orthotopically injected tumor cells without an effect on primary tumor growth. Taken together, these results indicated RKIP acted as a PCa metastasis suppressor gene. Evaluation of RKIP expression in clinical cases of PCa revealed that RKIP expression was moderate to high in non-neoplastic prostate, low in 50% of primary prostate cancers, and absent to low in the majority of metastases. Furthermore, low RKIP expression in primary prostate tumors was predictive of early tumor recurrence. Loss of RKIP was shown to induce resistance to radiation in PCa cells in vitro and in an in vivo murine model. Taken together, these studies indicate that RKIP plays multiple roles in PCa pathophysiology, suggesting that a method to increase RKIP expression in PCa may have therapeutic benefits.
 
Article
Nitric oxide (NO) is a short-lived pleiotropic regulator and is required for numerous pathophysiological functions, including macrophage-mediated immunity and cancer. It is a highly reactive free radical produced from l-arginine by different isoforms of NO synthases (NOSs). Sustained induction of inducible NOS (iNOS) during chronic inflammatory conditions leads to the formation of reactive intermediates of NO, which are mutagenic and cause DNA damage or impairment of DNA repair, alter cell signaling, and promote proinflammatory and angiogenic properties of the cell, thus contributing to carcinogenesis. Besides its well-established role in inflammation, increased expression of iNOS has been observed in colorectal tumors and other cancers. NO-related signaling pathways involved in colon tumorigenesis seem to progress through stimulation of proinflammatory cytokines and via posttranslational protein modifications of important antiapoptotic molecules in the tumors. NO can stimulate and enhance tumor cell proliferation by promoting invasive, angiogenic, and migratory activities. In contrast, studies also suggest that high levels of NO may be protective against tumor growth by inducing tumor cell death. However, a number of in vitro studies and particularly experimental animal data support the notion that NO and its reactive metabolite peroxynitrite stimulate cyclooxygenase-2 activity, leading to generation of prostaglandins that enhance tumor growth. These prostaglandins further augment tumor promotion and invasive properties of tumor cells. Hence, selective inhibitors of iNOS and combination strategies to inhibit both iNOS and cyclooxygenase-2 may have a preventive role in colon cancer.
 
Article
Hepatocellular carcinoma (HCC) accounts for 80-90% of primary liver tumors and is one of the most common and devastating malignant diseases worldwide. The MAPK signaling pathway is activated in over 90% of HCCs, and RKIP has been identified as an inhibitor of the MAPK pathway. It has been observed that downregulation of RKIP expression in HCC tumors contributes to constitutive activation of the ERK/MAPK pathway and promotes proliferation and migration of HCC cells. More important, activation of IGF-I/ERK/MAPK pathways can be blocked by restoration of RKIP levels. The protein levels of RKIP are significantly reduced in HCC, whereas mRNA levels only decreased in 41% of HCC samples studied, suggesting that the downregulation of RKIP in HCC may be influenced through multiple mechanisms both at the mRNA and protein levels. In this context, mTOR inhibitor, insulin, and proteasome inhibitors were found to modulate RKIP expression in FOCUS HCC cells. A better understating of mechanisms by which RKIP expression is downregulated in HCC may be critical to develop a possible target for therapeutic intervention of HCC.
 
Article
Although chemical mechanisms for the formation of nitrosothiol from •NO have been studied extensively "in the test tube", surprisingly little is known regarding the mechanism(s) of how nitrosothiols are formed in vivo. This lack of understanding has hampered more general acceptance of the concept of cysteine nitrosothiol formation as a generally applicable, regulated, and functionally significant protein posttranslational modification (as opposed to multiple other •NO-induced thiol modifications). Here we provide a brief overview/summary of the cellular formation of nitrosothiols from •NO via two possible mechanisms involving oxygen or transition metals.
 
Article
Nitric oxide (NO)-releasing agents such as JS-K and NO-releasing hybrids such as NO- and NONO-nonsteroidal anti-inflammatory drugs are novel agents with great potential for controlling cancer. Although studied extensively, a key question pertaining to their molecular targets and mechanism of action remains unclear: the role of NO in the overall biological effect of these agents. It has been shown that NO can directly modify sulfhydryl residues of proteins through S-nitrosylation and induce apoptosis. We showed that 3 structurally diverse NO-nonsteroidal anti-inflammatory drugs S-nitrosylated nuclear factor-κB p65 in vitro and in vivo and also showed that these agents S-nitrosylated caspase-3 in vivo. JS-K reduced nuclear β-catenin and cyclin D1 protein levels without affecting cytosolic β-catenin expression. On the basis of a time course study, S-nitrsolyation of nuclear β-catenin was determined to precede its degradation. These data provide a mechanistic role for NO and a rationale for the chemopreventive effects of these novel agents.
 
Article
Multiple myeloma (MM) is the second most common hematological and incurable malignancy of plasma cells with low proliferative activity in the bone marrow. MM patients initially respond to conventional therapy, however, many develop resistance and recurrences occur. We have identified RKIP as a novel gene product that is differentially overexpressed in MM cell lines and MM tissues compared to other studied tumors and normal bone marrow. This overexpression consisted, in large part, of a phosphorylated inactive form of RKIP at Ser153 (p-Ser153 RKIP). In contrast to RKIP, p-Ser153 RKIP lacks its ability to inhibit the MAPK signaling pathway. The overexpression of p-Ser153 RKIP in MM cell lines and MM tissues was further validated in a mouse model carrying a human MM xenograft, namely, LAGλ-1B. Bioinformatic analyses from databases support the presence of increased RKIP mRNA expression in MM compared to normal plasma cells. In these databases, high RKIP levels in MM are also correlated with the nonhyperdiploid status and the presence of IgH translocations, parameters that generally display more aggressive clinical features and shorter patients' survival irrespective of the treatment. Since RKIP expression regulates both the NF-κB and MAPK survival pathways, the overexpression of "inactive" p-Ser153 RKIP in MM might contribute positively to the overall cell survival/antiapoptotic phenotype and drug resistance of MM through the constitutive activation of survival pathways and downstream the transcription of anti-apoptotic gene products. The overexpression of RKIP and p-Ser153 RKIP in MM is the first demonstration in the literature, since in most tumor tissues the expression of RKIP is very low and the expression of p-Ser153 RKIP is much lower. The relationship between the levels of active RKIP and inactive p-Ser153 RKIP in MM may be of prognostic significance, and the regulation of RKIP activity may be a target for therapeutic intervention.
 
Article
Cross-regulation between the Wnt and nuclear factor (NF)-κB signaling pathways has emerged as an important area for the regulation of a diverse array of genes and pathways active in chronic inflammation, immunity, development, and tumorigenesis. The ligands, kinases, transcription factors, and products of their target gene expression are involved in cross-regulation of these two signaling pathways. Both β-catenin and NF-κB activate inducible nitric oxide synthase (iNOS) gene expression; however, β-catenin also exerts an inhibitory effect on NF-κB-mediated transcriptional activation, including iNOS. The recent discovery of functional cross-regulation between these two pathways has shown complex roles for Wnt/β-catenin and NF-κB signaling in the pathogenesis of certain cancers and other diseases. This review focuses on the molecular mechanisms of cross-regulation between Wnt/β-catenin and NF-κB signaling pathways in cancer cells.
 
Article
HIV infection is associated with a greatly elevated risk for the development of non-Hodgkin lymphoma (NHL), which while diminished, remains elevated in the highly active antiretroviral therapy (HAART) era. Chronic B cell activation, driven by contact with HIV virions, B cell-stimulatory cytokines, viruses (EBV, HPV, HCV), and by high levels of antigenic stimulation occurs in HIV infected persons, and it is seen at even higher levels in those who go on to develop AIDS-NHL. Evidence from multiple studies indicates that elevated serum levels of several B cell-stimulatory cytokines and biomarkers are seen preceding AIDS-NHL, as well as in immunocompetent persons that develop NHL. Phenotypic changes in circulating B cells also are seen preceding AIDS-NHL, including the expression of AICDA, and of cell-surface molecules and miRNA that are associated with activated B cells. HAART only partially normalizes the immune system of treated HIV+ persons as they still show clear evidence for ongoing inflammation and immune activation in, even those who show complete suppression of HIV viremia. Together, this provides ample evidence to support the notion that chronic activation of B cells contributes to the genesis of B cell lymphomas.
 
Article
Measurement of circulating cytokine levels can provide important information in the study of the pathogenesis of disease. John L. Fahey was a pioneer in the measurement of circulating cytokines and immune-activation markers and a leader in the quality assessment/control of assays for measurement of circulating cytokines. Insights into the measurement of circulating cytokines, including consideration of multiplex assays, are presented here.
 
Article
Colorectal cancer is the fourth leading cause of cancer-related deaths worldwide. Combination chemotherapy, including camptothecin (CPT) derivatives, is considered one of the standard first-line treatments. We found that in CPT-sensitive colon cancer cell lines, Raf kinase inhibitor protein (RKIP) was robustly induced following CPT treatment. Furthermore, ectopic RKIP is able to reverse resistance to CPT in human tumor cell lines thus making RKIP an important determinant of CPT sensitivity. It has been shown that elevated RKIP expression inhibits a number of cell-signaling pathways, including signal transducer and activator of transcription3 (STAT3). Given that STAT3 activation leads to metastasis in colon cancer and suppression of STAT3 signaling leads to the demise of tumor cells, a close relationship between uncontrolled STAT3 activation and the cancerous phenotype has been established. In colorectal cancer, RKIP expression is reduced in lymph node metastases, suggesting that high RKIP expression may prevent patient disease progression. Our results indicate that overexpression of RKIP inhibits interleukin-6 (IL-6)-, JAK-, and c-Src-mediated STAT3 activation and phosphorylation. From these data, we hypothesize that overexpression of RKIP may be predictive of disease outcome and provide a useful target for therapeutic intervention. Specifically, we predict that elevated RKIP levels, through the inhibition of STAT3 activation, decreases the potential for metastasis of human colon cancer.
 
Article
In traditional Chinese medicine, selected points on the body surface, the acupuncture points, are treated by various physical stimuli. Degranulation of subcutaneous mast cells has been suggested to be involved in initiation of the acupuncture effects. Here we give an overview on our recent research illustrating that ion channels in mast cell membranes can be activated by mechanical and red-laser-light stimuli. These stimuli can induce degranulation of the human mast cell line HMC1 as well as mast cells in connective tissue of rats. For HMC1 we also could show that the stimulation led to an increase in intracellular Ca2+. Activation of transient receptor potential channels sensitive to valinoid (TRPV) may be involved in initiation of the degranulation process. A stretch-activated anion channel may also be involved.
 
Article
During the last decade, probiotics have been established to be important mediators of host immunity. Their effects on both innate and adaptive immunity have been documented in the literature. Although several reports have correlated different strains of bacteria as probiotics, their effects on immunity vary. Clearly, there is a complex interplay between various constituents of probiotics and the immune response in humans. The role of probiotics on natural killer (NK) cells in the gut has been the subject of a few reports. In this review, we summarize the reported findings on the role of probiotics in the activation of gut-associated NK cells and the response of NK cells to stimuli elicited by probiotics and their microenvironment. The effects of probiotics on the activation of NK cells and their secretion of immune factors (e.g., interferon-γ, tumor necrosis factor-α, interleukin-2, etc.) are discussed in regard to their clinical significance in various diseases. Current investigations are being pursued, in particular, on the role of probiotics-activated NK cells in promoting the adaptive immune response against pathogens.
 
Article
A prominent feature of successful photodynamic therapy (PDT) is the targeting of mitochondria, because these organelles are critical sites for initiating both necrotic and apoptotic cell death. Among the variety of structures identified as targets for PDT, the outer membrane (OMM)- bound translocator protein, TSPO (formerly known as the peripheral benzodiazepine receptor), is of particular interest because it binds photosensitizers such as dicarboxylic porphyrins with nanomolar affinity and it is present at elevated levels in cancer cells. TSPO has also been postulated to be a component of the mitochondrial permeability transition (PT) pore (PTP), a protein channel that opens in the inner membrane (IMM) under the action of various stimuli, mainly matrix Ca2+ overload and oxidative stress, leading the cell toward death. In this study, photooxidation experiments with porphyrins indicated a strict correlation between porphyrin affinity for TSPO and the extent of mitochondrial photosensitization; moreover, they revealed a dual role of TSPO: (1) as a transport protein that facilitates diffusion of porphyrins into IMM, and (2) as a PTP regulatory protein when it binds porphyrins at its selective sites. Only photoactivation of TSPO-bound porphyrins leads to the opening of the PTP and mitochondrial dysfunction, whereas photoactivation of IMM-bound porphyrins maintains the PTP in the closed state.
 
Article
The Kruppel-like transcription factor 4 (KLF4) is a member of a large family of Kruppel-like transcription factors. KLF4 exerts many functions in both normal and cancerous tissues. In cancer, KLF4 has been reported to act either as an oncogene or tumor suppressor. It is also involved in the regulation of cancer stem cells and resistance to cytotoxic therapeutics. The expression of KLF4 messenger RNA (mRNA) in a variety of hematologic and solid malignancies has been analyzed by bioinformatics. In the majority of the studied cancers, the findings reveal that the high expression levels of KLF4 were associated with tumor progression and that KLF4 was thus acting as an oncogene. In a small number of cancers, the expression level of KLF4 was associated with tumor regression and KLF4 was therefore acting as a tumor suppressor. The data analyzed herein by bioinformatics extended the findings reported in the literature for a few cancers and assigned KLF4 as either an oncogene or tumor suppressor for all cancers studied. The findings derived from bioinformatics require experimental validation. Hence, the expression level of KLF4 may be of prognostic significance for certain cancers, and furthermore, targeting KLF4 may be a potential therapeutic when it acts as an oncogene. We suggest the application of inhibitors specific for KLF4, alone or in combination with conventional therapies, in clinical trials for the reversal of resistance and for tumor suppression.
 
Article
Premature infants are at increased risk for morbidity and mortality due to necrotizing enterocolitis (NEC) and sepsis. Probiotics decrease the risk of NEC and death in premature infants; however, mechanisms of action are unclear. A wide variety of probiotic species have been evaluated for potential beneficial properties in vitro, in animal models, and in clinical trials of premature infants. Although there is variation by species and even strain, common mechanisms of protection include attenuation of intestinal inflammation, apoptosis, dysmotility, permeability, supplanting other gut microbes through production of bacteriocins, and more effective use of available nutrients. Here, we review the most promising probiotics and what is known about their impact on the innate and adaptive immune response.
 
Article
Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death worldwide. It is often diagnosed at an advanced or metastatic stage and results of the approved systemic therapies are discouraging, making PDAC one of most lethal cancers in Western countries. In recent years, a better comprehension of PDAC unique biology has disclosed new potential targets for therapeutic interventions. Meanwhile, the development of conjugated agents, small molecules, antibodies, and immunoagents has opened therapeutic opportunities for drugs able to exert therapeutic effects on druggable targets of PDAC biology. Despite some failures, this approach is bringing meaningful results from bench to bedside, and more efficacious therapeutic opportunities may become available for PDAC treatment. In this review, we discuss the main hallmarks of PDAC biology as its microenvironment, cancerdriving proliferative pathways, growth suppression loops, and how PDAC evades immune system surveillance, as well as molecular aspects of each feature. The main preclinical and clinical results of each targeted intervention are also presented considering its biological rationale. Ongoing clinical trials provide evidence of the effectiveness of this approach and promising results in the treatment of PDAC.
 
Article
The use of chimeric antigen receptors (CARs) to redirect T cells against tumor-associated antigen targets is a powerful new approach to cancer immunotherapy. Recently, published phase I clinical trials and case reports suggest that this strategy has the potential to transform modern management of patients with B-cell-derived hematologic malignancies. Indeed, few precedents for novel therapies have achieved comparable therapeutic efficacy when evaluated for the first time in patients with otherwise untreatable malignant disease. One of several arising questions is how this impressive "proof of concept" can be extended to the treatment of solid tumors, which account for the vast majority of the cancer burden. Additional issues about the safety and potential for widespread use of this approach also remain to be addressed. Here, we summarize recent developments in the preclinical and early-phase clinical evaluation of CAR T-cell immunotherapy. We also discuss some of the obstacles to the broader clinical development of this exciting new therapeutic modality and how current preclinical studies are attempting to address these shortcomings.
 
Article
Gut microbiota have a key role in the maintenance of intestinal integrity, but chemotherapy can induce major changes in the composition and gene function of gut microbiota. Such modifications may contribute to the development of gastrointestinal mucositis. The prevention of cancer therapy-induced mucositis has been investigated in clinical trials with promising results. The role of gut microbiota is important not only in the development of adverse events but also for immune-related therapeutic effects. Thus, gut microbiota may be an essential partner of chemotherapy in improving patient outcomes.
 
Article
Nitric oxide (NO) is a novel cancer therapeutic, and NO donors provide a unique advantage in the study of the properties of NO as an antineoplastic agent because they exhibit novel anti-tumor sensitizing abilities and reverse resistance to cytotoxic therapies. We present evidence on the enhancement by NO, used in combination with chemotherapy, of drug-induced apoptosis in colorectal cancer cells and NO-mediated regression of tumor xenografts resistant to conventional chemo- and radiotherapeutic interventions. Treatment with (Z)-l-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETANONOate) sensitized SW620 metastatic CRC cells to cisplatin (CDDP)-induced apoptosis. Nude mice bearing SW620 xenografts treated with CDDP and DETANONOate demonstrated a 36% reduction in tumor load compared with control, and this was associated with an up-regulation of the expression of the apoptosis-inducing factor (AIF). Similarly, in models of rectal cancer, pretreating radio-resistant HT-29 colorectal cancer cells with DETANONOate for 16 h prior to ionizing radiation resulted in a significant reduction in colony formation (47%) compared with DETANONOate treatment alone. In vivo, SCID mice bearing HT-29 xenografts and treated with irradiation, DETANONOate, or a combination showed tumor growth reduction by 32.5% following the combination treatment. In vitro, the sensitizing activity of DETANONOate was associated with an up-regulation of p21, p27, and BAX, with a concomitant decrease in Bcl-2 expression in DETANONOate-pretreated HT-29 cells compared with controls. Altogether, these results demonstrate that DETANONOate is a potent chemo-radio-sensitizer in colorectal cancer cells that are resistant to conventional chemo- and radiotherapies.
 
Article
Several protozoa are recognized etiological agents of dangerous water- and vector-borne diseases, and some of them are among the most dangerous and deadly of human pathogens. Diseases such as amoebiasis, leishmaniasis, trypanosomiasis, and malaria are among the most fatal infections for humans. Despite major advances in medicine in the last century, infectious diseases continue to present enormous global health problems. Antibiotic therapy for the infections caused by pathogenic protozoa is generally empirical, and patient recovery is often problematic, but some forms of combination therapy have proven more successful than single-drug therapies. New approaches that are effective, affordable, and widely applicable and that are not susceptible to resistance are urgently needed. The effectiveness of antimicrobial photodynamic therapy (PDT) as a novel mode of treating some diseases caused by eukaryotic microorganisms has been demonstrated against some protozoan pathogenic species. PDTs offer alternative approaches in the medical and environmental control of pathogenic agents as well as the sterilization of blood products.
 
Article
Natural products and their synthetic analogs are widely used as anticancer drugs. Many anticancer drugs originated from cytotoxic compounds, and most have been shown to induce apoptosis in cancer cells. Based on the variety of their modes of action, the identification of new cytotoxic compounds may lead to the discovery of new types of drugs. Recently, much attention has been given to the metabolites of marine organisms due to their strong cytotoxicity. For example, eribulin mesylate, a synthetic analog of halichondrin B isolated from H. okadai Kadota, has been developed as an anticancer drug. Novel cytotoxic substances, such as halichonines, bisebromoamides, and biselyngbyasides, have been isolated from marine organisms as apoptosis-inducing agents. All of these compounds may possess therapeutic potential, and thus, efforts to identify new apoptosis-inducing agents of marine origin may contribute to the discovery of new pharmaceuticals.
 
Article
Energy and energy equivalents are mainly produced in mitochondria. Thus, the continuous functionality and integrity of mitochondria are of high importance for cell health and survival, and this is especially the case in long-lived cells with a prolonged postmitotic phase, e.g., endothelial cells or neurons. Mitochondrial functionality and integrity is achieved by the quality control mechanisms of mitochondrial dynamics (i.e., fission and fusion) and autophagy (i.e., mitophagy). In senescent cells, a decline of both mitochondrial quality control mechanisms is observed, and in Parkinson's disease mitochondrial dysfunction is mediated by impaired quality control. These characteristics are discussed as causes for the development and/or progression of Parkinson's disease. Here we review the effect of oxidative stress on quality control in different in vitro aging cell models and Parkinson's disease cell models, underlining the importance of mitochondrial dynamics and autophagy for cell fitness.
 
CD4 Point of care (POC) testing devices summary 
Article
Foundational cellular immunology research of the 1960s and 1970s, together with the advent of monoclonal antibodies and flow cytometry, provided the knowledge base and the technological capability that enabled the elucidation of the role of CD4 T cells in HIV infection. Research identifying the sources and magnitude of variation in CD4 measurements, standardized reagents and protocols, and the development of clinical flow cytometers all contributed to the feasibility of widespread CD4 testing. Cohort studies and clinical trials provided the context for establishing the utility of CD4 for prognosis in HIV-infectedpersons, initial assessment of in vivo antiretroviral drug activity, and as a surrogate marker for clinical outcome in antiretroviral therapeutic trials. Even with sensitive HIV viral load measurement, CD4 cell counting is still utilized in determining antiretroviral therapy eligibility and time to initiate therapy. New point of care technologies are helping both to lower the cost of CD4 testing and enable its use in HIV test and treat programs around the world.
 
Article
John Fahey was an integral member of the small group of investigators who developed the Multicenter AIDS Cohort Study (MACS) in the early 1980s. A major research theme in the MACS was defining immune system changes in men at risk for developing AIDS. John's experience and expertise provided a solid grounding for the immunologic investigations conducted in the MACS. Additionally, he contributed enormously to the science of the MACS and pioneered the critical evaluation of serologic methods of documenting infection with HIV and T cell phenotyping. Perhaps most importantly, John recruited key new investigators to the MACS, and worked closely with the original MACS investigators to create a structure that promoted scientific innovation, openness, and the ability to quickly respond to emerging research themes.
 
Article
Antibody drug conjugates (ADCs) and immunotoxins are second-generation anticancer therapeutics that directly target cancerous cells and deliver toxic molecules that inhibit the cancer's proliferation. They are composed of an antibody domain that binds the target cell, linked to a toxic molecule that inhibits cell proliferation. Utilization of these potent and effective therapies is limited by the high cost and complexity of manufacturing these chimeric molecules. ADCs are currently made by chemically linking an antibody produced by a mammalian cell culture to a toxic drug molecule. Unlike ADCs, immunotoxins utilize protein toxins derived from bacteria or plants, and are often genetically linked to the antibody domain. Protein toxins typically target eukaryotic translations. Because these toxins target eukaryotic translation, they cannot be produced in eukaryotic expression. Production of these chimeric molecules in bacteria is also limited due to the lack of sophisticated protein-folding machinery, which is required to fold complex immunotoxin proteins. To overcome the challenges associated with the production of immunotoxins, chloroplasts of the eukaryotic green alga Chlamydomonas reinhardtii were recently developed as an expression host. Chloroplasts contain complex protein-folding machinery, including chaperones and protein disulfide isomerases, but have a translational apparatus (70S ribosomes and elongation factors) that resembles that of a bacterium, leaving them unharmed by toxins that target the eukaryotic translational apparatus. In addition, chloroplasts are capable of producing multivalent immunotoxins, which increases the capability of these molecules to inhibit the proliferation of cancer cells. Development of this new technology will allow the production of more complex and effective immunotoxins, while potentially reducing the complexity of production of these valuable cancer therapies.
 
Article
Several reports have shown that the formation of stable water clusters (SWC) of different sizes underlie their physical and chemical properties, such as temperature-related density and anomalous melting at high temperature. Among the SWCs, one produces a double helix (DH), a structure that has been studied in a variety of biological systems. The major objective of this preliminary study was to investigate the effects of SWCs on several phenotypic and molecular characteristics of human cancer cell lines. Our previous findings have demonstrated that very high dilutions of chemical/biological agents, while having no direct observed effects on human cellular systems, can nevertheless induce molecular and genetic changes that contribute to signaling by other stimuli. These findings suggested that cells can respond to relatively fewer molecules than physiological levels comprising of high number of molecules. Accordingly, we hypothesized that treatment of cells with a water preparation containing SWCs would induce molecular and genetic changes in human cellular systems. This hypothesis was tested using human melanoma cell lines as a model for an in vitro analysis. We examined the effect of SWCs on cell viability, proliferation, expression of immune death receptors and response to deathligand−induced apoptosis. In addition, we examined whether genetic changes might have also taken place. The preliminary findings demonstrate that treatment of melanoma cell lines with SWCs inhibits cell proliferation, upregulates the expression of death receptors, sensitizes the tumor cells to FasL-induced apoptosis, and selectively modifies gene products that regulate growth and the apoptotic pathways.
 
Article
Alternative scaffold proteins are a growing class of engineered binding proteins that can be identifiedusing modern protein-engineering technologies. From large combinatorial libraries, high-quality binders can be generated essentially against any target protein of interest. Typically, these binding proteins have favorable properties in terms of size, stability, or ease of production. In this review, we focus on alternative scaffold binders for applicationsmainly in oncology. We highlight recent advances in the field and provide a perspective on the potentials and challenges in the drug development process of these molecules.
 
Article
Opioids are still the most powerful drug in the treatment of acute and chronic pain. They comprise a class of drugs also known as narcotic analgesics. Opioid agonists can activate central and peripheral opioid receptors. Opioid receptors belong to the family of G protein-coupled receptors, which includes the typical structure of seven putative transmembrane (TM) regions. Opioid receptors are prototypical Gi/Go-coupled receptors because opioid signals are efficiently blocked by pertussis toxin, a bacterial toxin produced by Bordetella pertussis that ADP-ribosylates and inactivates the α subunits of Gi/Go proteins. The prolonged activation by opioids leads to the expression of compensating mechanisms in many neurons or neuronal systems. Soon after the discovery of opiate receptors it was reported that brain extracts contain a factor that inhibits acetylcholine release from nerves in the guinea pig ileum in a naloxone-reversible fashion, and that electrical stimulation of specific brain regions in rats elicited a profound analgesia, which was reversible by naloxone. After a century of effort, opioids remain the most effective treatment against pain. Most painkillers, such as aspirin, have an upper limit to their painkilling level, but opioids block more and more pain with increasing doses. Opioids are far from perfect, however; ongoing efforts by chemists and pharmacologists will continue to deliver new opioid drugs with higher potency and a reduction in severe side effects.
 
Article
Inflammatory milieu is associated with cancer progression and angiogenesis in different types of tumors, such as gastrointestinal, breast, prostate, and head and neck cancers. Among the inflammatory pathways, numerous evidence indicates that the cyclooxygenase-2/microsomal prostaglandin E synthase-1/prostaglandin E2/E Prostaglandin type receptor (COX-2/mPGES-1/PGE2/EPs) signaling supports epithelial tumor aggressiveness promoting cell growth, epithelial-mesenchymal transition (EMT), and stemness. Further, PGE2 modulates pro-oncogenic and pro-angiogenic pathways such as EGFR and FGFR-1. In this review, we discuss the role of PGE2 and its network of partner proteins in tumor progression and angiogenesis. We also discuss major COX-2/mPGES-1 and EPs therapeutic advances that have been made over the past few years in targeting tumorigenesis and angiogenesis.
 
Article
Protein kinase C-mediated phosphorylation converts the raf kinase inhibitor protein (RKIP) into an inhibitor of the G protein-coupled receptor kinase 2 (GRK2). As a result of GRK2 inhibition, RKIP prevents receptor desensitization and enhances signaling stimulated by the classical substrate of GRK2, i.e., the Gscoupled b-adrenergic receptor. The Gq/11-coupled angiotensin II AT1 receptor is another prototypic substrate of GRK2 in the cardiovascular system. However, the role of RKIP in Gq/11-coupled receptor signaling is not clear. Here, we show that overexpression of RKIP in kidney cells led to a significant increase of the AT1-stimulated calcium signal. In contrast, a phosphorylation-deficient mutant of RKIP that cannot act as GRK2 inhibitor had no effect. Analogously to the signal sensitization of kidney cells, RKIP increased the angiotensin II-stimulated hypertrophic response of cardiomyocytes. RNA interference studies revealed that endogenous RKIP levels of kidney cells and cardiomyocytes were sufficient to produce signal enhancement of AT 1. Thus, RKIP acts as a physiological enhancer of angiotensin II-stimulated signaling in kidney cells and cardiomyocytes.
 
Article
Raf kinase inhibitor protein (RKIP) has been shown to be differentially regulated in a number of different human cancers. Typically, RKIP levels are found to be lower in tumor tissue than in normal tissue, and lower still in tumor metastases. In colorectal cancer (CRC), this is also the case; however interestingly in this disease, it has also been shown that the level of RKIP in the primary tumor correlates inversely with both the likelihood of metastatic relapse and with prognosis. Although this relationship with prognosis has clear clinical relevance, there is also some evidence that RKIP may provide even greater utility by acting as a predictive marker. In this review, we describe the evidence demonstrating the clear role for RKIP as a prognostic marker in CRC and go on to describe some of our evidence indicating a possible predictive role. Because there is as yet no mechanistic understanding of how low levels of RKIP affect prognosis in CRC, we have been using the RKIP knockout mouse to attempt to address this question. Here, we describe the current literature relating to the RKIP knockout mouse and our approach to using it to study the role of RKIP in CRC.
 
Article
Tumor tissues are composed of tumor cells as well as the surrounding stroma. The stroma consists of various kinds of cells and the extracellular matrix that together form the tumor microenvironment. Among them, stromal cells (fibroblast-like cells) can regulate the growth of tumor cells positively or negatively through the tumor-stromal cell interactions (TSIs). TSIs are mediated by secreted factors or direct adhesion. Thus, the growth of tumor cells may be able to be suppressed by modulation of TSIs. In this review, we introduce new strategies targeting the tumor microenvironment, especially TSIs. Molecular targets in TSIs and small molecule compounds that can modulate TSIs are discussed.
 
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Stravoula Baritaki
  • University of California, Los Angeles
Sara Huerta-Yepez
  • University of California, Los Angeles
Thomas Efferth
  • Johannes Gutenberg-Universität Mainz
Rebecca Porritt
  • Cedars-Sinai Medical Center
Najib Aziz
  • University of California, Los Angeles