Enhancement of Glioma Radiotherapy and Chemotherapy Response With Targeted Antibody Therapy Against Death Receptor 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiveash, John B.; Gillespie, G. Yancey; Oliver, Patsy G.

2008-06-01

Purpose: TRA-8 is an agonistic mouse monoclonal antibody that binds to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor 5, which induces apoptosis in cancer cells through a caspase-8-dependent mechanism. We investigated the ability of TRA-8 to augment the radiotherapy (RT) and chemotherapy response of human glioma cells in vitro and in vivo. Methods and Materials: The in vitro cytotoxicity of TRA-8 and temozolomide (Tmz) or RT was examined using adenosine triphosphate-dependent viability and clonogenic survival assays with five glioma cell lines. Death receptor 5 expression was determined by flow cytometry. In vivo studies included subcutaneous and intracranial xenograft modelsmore » testing various combination treatments, including RT, Tmz, and TRA-8. Results: TRA-8, combined with Tmz or RT, produced enhanced cytotoxicity against five glioma cell lines compared with the use of the individual agents alone. Death receptor 5 upregulation occurred in response to RT. Complete tumor regression in the subcutaneous experiments was the most common in animals that received combination therapy with TRA-8/Tmz/RT. TRA-8 enhanced tumor growth delay in combination with RT or Tmz. TRA-8 alone had limited activity against intracranial tumors. In contrast, the median survival of mice treated with TRA-8/Tmz/RT was significantly greater than the control or TRA-8-alone-treated mice. The median survival of the mice treated with TRA-8/Tmz/RT or chemoradiotherapy only was significantly greater than the control or TRA-8-treated mice. A trend toward improved survival was observed between TRA-8/Tmz/RT-treated and Tmz/RT-treated mice. Conclusions: These preliminary findings support the hypothesis that TRA-8 will augment the RT and chemotherapy response in gliomas. A humanized version of TRA-8 is being evaluated in a Phase II clinical trial.« less

Dual Agonist Surrobody Simultaneously Activates Death Receptors DR4 and DR5 to Induce Cancer Cell Death.

PubMed

Milutinovic, Snezana; Kashyap, Arun K; Yanagi, Teruki; Wimer, Carina; Zhou, Sihong; O'Neil, Ryann; Kurtzman, Aaron L; Faynboym, Alexsandr; Xu, Li; Hannum, Charles H; Diaz, Paul W; Matsuzawa, Shu-ichi; Horowitz, Michael; Horowitz, Lawrence; Bhatt, Ramesh R; Reed, John C

2016-01-01

Death receptors of the TNF family are found on the surface of most cancer cells and their activation typically kills cancer cells through the stimulation of the extrinsic apoptotic pathway. The endogenous ligand for death receptors 4 and 5 (DR4 and DR5) is TNF-related apoptosis-inducing ligand, TRAIL (Apo2L). As most untransformed cells are not susceptible to TRAIL-induced apoptosis, death receptor activators have emerged as promising cancer therapeutic agents. One strategy to stimulate death receptors in cancer patients is to use soluble human recombinant TRAIL protein, but this agent has limitations of a short half-life and decoy receptor sequestration. Another strategy that attempted to evade decoy receptor sequestration and to provide improved pharmacokinetic properties was to generate DR4 or DR5 agonist antibodies. The resulting monoclonal agonist antibodies overcame the limitations of short half-life and avoided decoy receptor sequestration, but are limited by activating only one of the two death receptors. Here, we describe a DR4 and DR5 dual agonist produced using Surrobody technology that activates both DR4 and DR5 to induce apoptotic death of cancer cells in vitro and in vivo and also avoids decoy receptor sequestration. This fully human anti-DR4/DR5 Surrobody displays superior potency to DR4- and DR5-specific antibodies, even when combined with TRAIL-sensitizing proapoptotic agents. Moreover, cancer cells were less likely to acquire resistance to Surrobody than either anti-DR4 or anti-DR5 monospecific antibodies. Taken together, Surrobody shows promising preclinical proapoptotic activity against cancer cells, meriting further exploration of its potential as a novel cancer therapeutic agent. ©2015 American Association for Cancer Research.

Dual agonist Surrobody™ simultaneously activates death receptors DR4 and DR5 to induce cancer cell death

PubMed Central

Milutinovic, Snezana; Kashyap, Arun K.; Yanagi, Teruki; Wimer, Carina; Zhou, Sihong; O' Neil, Ryann; Kurtzman, Aaron L.; Faynboym, Alexsandr; Xu, Li; Hannum, Charles H.; Diaz, Paul W.; Matsuzawa, Shu-ichi; Horowitz, Michael; Horowitz, Lawrence; Bhatt, Ramesh R.; Reed, John C.

2015-01-01

Death receptors of the Tumor Necrosis Factor (TNF) family are found on surface of most cancer cells and their activation typically kills cancer cells through the stimulation of the extrinsic apoptotic pathway. The endogenous ligand for death receptors-4 and -5 (DR4 and DR5) is Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand, TRAIL (Apo2L). Since most untransformed cells are not susceptible to TRAIL-induced apoptosis, death receptor activators have emerged as promising cancer therapeutic agents. One strategy to stimulate death receptors in cancer patients is to use soluble human recombinant TRAIL protein, but this agent has limitations of a short half-life and decoy receptor sequestration. Another strategy that attempted to evade decoy receptor sequestration and to provide improved pharmacokinetic properties was to generate DR4 or DR5 agonist antibodies. The resulting monoclonal agonist antibodies overcame the limitations of short half-life and avoided decoy receptor sequestration, but are limited by activating only one of the two death receptors. Here, we describe a DR4 and DR5 dual agonist produced using Surrobody™ technology that activates both DR4 and DR5 to induce apoptotic death of cancer cells in vitro and in vivo and also avoids decoy receptor sequestration. This fully human anti-DR4/DR5 Surrobody displays superior potency to DR4- and DR5-specific antibodies, even when combined with TRAIL-sensitizing pro-apoptotic agents. Moreover, cancer cells were less likely to acquire resistance to Surrobody than either anti-DR4 or anti-DR5 mono-specific antibodies. Taken together, Surrobody shows promising preclinical pro-apoptotic activity against cancer cells, meriting further exploration of its potential as a novel cancer therapeutic agent. PMID:26516157

Antigen-Specific Immune Modulation Targets mTORC1 Function To Drive Chemokine Receptor-Mediated T Cell Tolerance.

PubMed

Chen, Weirong; Wan, Xiaoxiao; Ukah, Tobechukwu K; Miller, Mindy M; Barik, Subhasis; Cattin-Roy, Alexis N; Zaghouani, Habib

2016-11-01

To contain autoimmunity, pathogenic T cells must be eliminated or diverted from reaching the target organ. Recently, we defined a novel form of T cell tolerance whereby treatment with Ag downregulates expression of the chemokine receptor CXCR3 and prevents diabetogenic Th1 cells from reaching the pancreas, leading to suppression of type 1 diabetes (T1D). This report defines the signaling events underlying Ag-induced chemokine receptor-mediated tolerance. Specifically, we show that the mammalian target of rapamycin complex 1 (mTORC1) is a major target for induction of CXCR3 downregulation and crippling of Th1 cells. Indeed, Ag administration induces upregulation of programmed death-ligand 1 on dendritic cells in a T cell-dependent manner. In return, programmed death-ligand 1 interacts with the constitutively expressed programmed death-1 on the target T cells and stimulates docking of Src homology 2 domain-containing tyrosine phosphatase 2 phosphatase to the cytoplasmic tail of programmed death-1. Active Src homology 2 domain-containing tyrosine phosphatase 2 impairs the signaling function of the PI3K/protein kinase B (AKT) pathway, leading to functional defect of mTORC1, downregulation of CXCR3 expression, and suppression of T1D. Thus, mTORC1 component of the metabolic pathway serves as a target for chemokine receptor-mediated T cell tolerance and suppression of T1D. Copyright © 2016 by The American Association of Immunologists, Inc.

Hedgehog inhibition promotes a switch from Type II to Type I cell death receptor signaling in cancer cells.

PubMed

Kurita, Satoshi; Mott, Justin L; Cazanave, Sophie C; Fingas, Christian D; Guicciardi, Maria E; Bronk, Steve F; Roberts, Lewis R; Fernandez-Zapico, Martin E; Gores, Gregory J

2011-03-31

TRAIL is a promising therapeutic agent for human malignancies. TRAIL often requires mitochondrial dysfunction, referred to as the Type II death receptor pathway, to promote cytotoxicity. However, numerous malignant cells are TRAIL resistant due to inhibition of this mitochondrial pathway. Using cholangiocarcinoma cells as a model of TRAIL resistance, we found that Hedgehog signaling blockade sensitized these cancer cells to TRAIL cytotoxicity independent of mitochondrial dysfunction, referred to as Type I death receptor signaling. This switch in TRAIL requirement from Type II to Type I death receptor signaling was demonstrated by the lack of functional dependence on Bid/Bim and Bax/Bak, proapoptotic components of the mitochondrial pathway. Hedgehog signaling modulated expression of X-linked inhibitor of apoptosis (XIAP), which serves to repress the Type I death receptor pathway. siRNA targeted knockdown of XIAP mimics sensitization to mitochondria-independent TRAIL killing achieved by Hedgehog inhibition. Regulation of XIAP expression by Hedgehog signaling is mediated by the glioma-associated oncogene 2 (GLI2), a downstream transcription factor of Hedgehog. In conclusion, these data provide additional mechanisms modulating cell death by TRAIL and suggest Hedgehog inhibition as a therapeutic approach for TRAIL-resistant neoplasms.

Targeting breast to brain metastatic tumours with death receptor ligand expressing therapeutic stem cells

PubMed Central

Bagci-Onder, Tugba; Du, Wanlu; Figueiredo, Jose-Luiz; Martinez-Quintanilla, Jordi

2015-01-01

Characterizing clinically relevant brain metastasis models and assessing the therapeutic efficacy in such models are fundamental for the development of novel therapies for metastatic brain cancers. In this study, we have developed an in vivo imageable breast-to-brain metastasis mouse model. Using real time in vivo imaging and subsequent composite fluorescence imaging, we show a widespread distribution of micro- and macro-metastasis in different stages of metastatic progression. We also show extravasation of tumour cells and the close association of tumour cells with blood vessels in the brain thus mimicking the multi-foci metastases observed in the clinics. Next, we explored the ability of engineered adult stem cells to track metastatic deposits in this model and show that engineered stem cells either implanted or injected via circulation efficiently home to metastatic tumour deposits in the brain. Based on the recent findings that metastatic tumour cells adopt unique mechanisms of evading apoptosis to successfully colonize in the brain, we reasoned that TNF receptor superfamily member 10A/10B apoptosis-inducing ligand (TRAIL) based pro-apoptotic therapies that induce death receptor signalling within the metastatic tumour cells might be a favourable therapeutic approach. We engineered stem cells to express a tumour selective, potent and secretable variant of a TRAIL, S-TRAIL, and show that these cells significantly suppressed metastatic tumour growth and prolonged the survival of mice bearing metastatic breast tumours. Furthermore, the incorporation of pro-drug converting enzyme, herpes simplex virus thymidine kinase, into therapeutic S-TRAIL secreting stem cells allowed their eradication post-tumour treatment. These studies are the first of their kind that provide insight into targeting brain metastasis with stem-cell mediated delivery of pro-apoptotic ligands and have important clinical implications. PMID:25910782

Targeted Silencing of Anthrax Toxin Receptors Protects against Anthrax Toxins*

PubMed Central

Arévalo, Maria T.; Navarro, Ashley; Arico, Chenoa D.; Li, Junwei; Alkhatib, Omar; Chen, Shan; Diaz-Arévalo, Diana; Zeng, Mingtao

2014-01-01

Anthrax spores can be aerosolized and dispersed as a bioweapon. Current postexposure treatments are inadequate at later stages of infection, when high levels of anthrax toxins are present. Anthrax toxins enter cells via two identified anthrax toxin receptors: tumor endothelial marker 8 (TEM8) and capillary morphogenesis protein 2 (CMG2). We hypothesized that host cells would be protected from anthrax toxins if anthrax toxin receptor expression was effectively silenced using RNA interference (RNAi) technology. Thus, anthrax toxin receptors in mouse and human macrophages were silenced using targeted siRNAs or blocked with specific antibody prior to challenge with anthrax lethal toxin. Viability assays were used to assess protection in macrophages treated with specific siRNA or antibody as compared with untreated cells. Silencing CMG2 using targeted siRNAs provided almost complete protection against anthrax lethal toxin-induced cytotoxicity and death in murine and human macrophages. The same results were obtained by prebinding cells with specific antibody prior to treatment with anthrax lethal toxin. In addition, TEM8-targeted siRNAs also offered significant protection against lethal toxin in human macrophage-like cells. Furthermore, silencing CMG2, TEM8, or both receptors in combination was also protective against MEK2 cleavage by lethal toxin or adenylyl cyclase activity by edema toxin in human kidney cells. Thus, anthrax toxin receptor-targeted RNAi has the potential to be developed as a life-saving, postexposure therapy against anthrax. PMID:24742682

Fas-associated Protein with Death Domain (FADD)-independent Recruitment of c-FLIPL to Death Receptor 5*

PubMed Central

Jin, Tai-Guang; Kurakin, Alexei; Benhaga, Nordine; Abe, Karon; Mohseni, Mehrdad; Sandra, Ferry; Song, Keli; Kay, Brian K.; Khosravi-Far, Roya

2010-01-01

Here we show a novel mechanism by which FLICE-like inhibitory protein (c-FLIP) regulates apoptosis induced by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and one of its receptors, DR5. c-FLIP is a critical regulator of the TNF family of cytokine receptor signaling. c-FLIP has been postulated to prevent formation of the competent death-inducing signaling complex (DISC) in a ligand-dependent manner, through its interaction with FADD and/or caspase-8. In order to identify regulators of TRAIL function, we used the intracellular death domain (DD) of DR5 as a target to screen a phage-displayed combinatorial peptide library. The DD of DR5 selected from the library a peptide that showed sequence similarity to a stretch of amino acids in the C terminus of c-FLIPL. The phage-displayed peptide selectively interacted with the DD of DR5 in in vitro binding assays. Similarly, full-length c-FLIP (c-FLIPL) and the C-terminal p12 domain of c-FLIP interacted with DR5 both in in vitro pull-down assays and in mammalian cells. This interaction was independent of TRAIL. To the contrary, TRAIL treatment released c-FLIPL from DR5, permitting the recruitment of FADD to the active DR5 signaling complex. By employing FADD-deficient Jurkat cells, we demonstrate that DR5 and c-FLIPL interact in a FADD-independent manner. Moreover, we show that a cellular membrane permeable version of the peptide corresponding to the DR5 binding domain of c-FLIP induces apoptosis in mammalian cells. Taken together, these findings indicate that c-FLIPL interacts with the DD of DR5, thus preventing death signaling by DR5 prior to the formation of an active DISC. Because TRAIL and DR5 are ubiquitously expressed, the interaction of c-FLIPL and DR5 indicates a mechanism by which tumor selective apoptosis can be achieved through protecting normal cells from undergoing death receptor-induced apoptosis. PMID:15485835

Glucose Deprivation Induces ATF4-Mediated Apoptosis through TRAIL Death Receptors

PubMed Central

Iurlaro, Raffaella; Püschel, Franziska; León-Annicchiarico, Clara Lucía; O'Connor, Hazel; Martin, Seamus J.; Palou-Gramón, Daniel; Lucendo, Estefanía

2017-01-01

ABSTRACT Metabolic stress occurs frequently in tumors and in normal tissues undergoing transient ischemia. Nutrient deprivation triggers, among many potential cell death-inducing pathways, an endoplasmic reticulum (ER) stress response with the induction of the integrated stress response transcription factor ATF4. However, how this results in cell death remains unknown. Here we show that glucose deprivation triggered ER stress and induced the unfolded protein response transcription factors ATF4 and CHOP. This was associated with the nontranscriptional accumulation of TRAIL receptor 1 (TRAIL-R1) (DR4) and with the ATF4-mediated, CHOP-independent induction of TRAIL-R2 (DR5), suggesting that cell death in this context may involve death receptor signaling. Consistent with this, the ablation of TRAIL-R1, TRAIL-R2, FADD, Bid, and caspase-8 attenuated cell death, although the downregulation of TRAIL did not, suggesting ligand-independent activation of TRAIL receptors. These data indicate that stress triggered by glucose deprivation promotes the ATF4-dependent upregulation of TRAIL-R2/DR5 and TRAIL receptor-mediated cell death. PMID:28242652

Folate receptor 1 (FOLR1) targeted chimeric antigen receptor (CAR) T cells for the treatment of gastric cancer

PubMed Central

Pyo, Suhkneung; Kang, Chung Hyo; Lee, Chong Ock; Lee, Heung Kyoung; Choi, Sang Un; Park, Chi Hoon

2018-01-01

Gastric cancer is a malignancy that has a high mortality rate. Although progress has been made in the treatment of gastric cancer, many patients experience cancer recurrence and metastasis. Folate receptor 1 (FOLR1) is overexpressed on the cell surface in over one-third of gastric cancer patients, but rarely is expressed in normal tissue. This makes FOLR1 a potential target for chimeric antigen receptor (CAR) T cell immunotherapy, although the function of FOLR1 has not been elucidated. CAR are engineered fusion receptor composed of an antigen recognition region and signaling domains. T cells expressing CAR have specific activation and cytotoxic effects against cancer cells containing the target antigen. In this study, we generated a CAR that targets FOLR1 composed of a single-chain variable fragment (scFv) of FOLR1 antibody and signaling domains consisting of CD28 and CD3ζ. Both FOLR1-CAR KHYG-1, a natural killer cell line, and FOLR1-CAR T cells recognized FOLR1-positive gastric cancer cells in a MHC-independent manner and induced secretion of various cytokines and caused cell death. Conclusively, this is the first study to demonstrate that CAR KHYG-1/T cells targeting FOLR1 are effective against FOLR1-positive gastric cancer cells. PMID:29874279

Cell death sensitization of leukemia cells by opioid receptor activation

PubMed Central

Friesen, Claudia; Roscher, Mareike; Hormann, Inis; Fichtner, Iduna; Alt, Andreas; Hilger, Ralf A.; Debatin, Klaus-Michael; Miltner, Erich

2013-01-01

Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies. PMID:23633472

Epidermal growth factor receptor and variant III targeted immunotherapy

PubMed Central

Congdon, Kendra L.; Gedeon, Patrick C.; Suryadevara, Carter M.; Caruso, Hillary G.; Cooper, Laurence J.N.; Heimberger, Amy B.; Sampson, John H.

2014-01-01

Immunotherapeutic approaches to cancer have shown remarkable promise. A critical barrier to successfully executing such immune-mediated interventions is the selection of safe yet immunogenic targets. As patient deaths have occurred when tumor-associated antigens shared by normal tissue have been targeted by strong cellular immunotherapeutic platforms, route of delivery, target selection and the immune-mediated approach undertaken must work together to maximize efficacy with safety. Selected tumor-specific targets can spare potential toxicity to normal tissue; however, they are far less common than tumor-associated antigens and may not be present on all patients. In the context of immunotherapy for high-grade glioma, 2 of the most prominently studied antigens are the tumor-associated epidermal growth factor receptor and its tumor-specific genetic deletion variant III. In this review, we will summarize the immune-mediated strategies employed against these targets as well as the caveats particular to these approaches. PMID:25342601

Akt-phosphorylated Mitogen-activated Kinase-activating Death Domain Protein (MADD) Inhibits TRAIL-induced Apoptosis by Blocking Fas-associated Death Domain (FADD) Association with Death Receptor 4*

PubMed Central

Li, Peifeng; Jayarama, Shankar; Ganesh, Lakshmy; Mordi, David; Carr, Ryan; Kanteti, Prasad; Hay, Nissim; Prabhakar, Bellur S.

2010-01-01

MADD plays an essential role in cancer cell survival. Abrogation of endogenous MADD expression results in significant spontaneous apoptosis and enhanced susceptibility to tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. However, the regulation of MADD function is largely unknown. Here, we demonstrate that endogenous MADD is phosphorylated at three highly conserved sites by Akt, and only the phosphorylated MADD can directly interact with the TRAIL receptor DR4 thereby preventing Fas-associated death domain recruitment. However, in cells susceptible to TRAIL treatment, TRAIL induces a reduction in MADD phosphorylation levels resulting in MADD dissociation from, and Fas-associated death domain association with DR4, which allows death-inducing signaling complex (DISC) formation leading to apoptosis. Thus, the pro-survival function of MADD is dependent upon its phosphorylation by Akt. Because Akt is active in most cancer cells and phosphorylated MADD confers resistance to TRAIL-induced apoptosis, co-targeting Akt-MADD axis is likely to increase efficacy of TRAIL-based therapies. PMID:20484047

Acute myeloid leukemia-targeted toxin activates both apoptotic and necroptotic death mechanisms.

PubMed

Horita, Henrick; Frankel, Arthur E; Thorburn, Andrew

2008-01-01

Acute myelogenous leukemia (AML) is the second most common leukemia with approximately 13,410 new cases and 8,990 deaths annually in the United States. A novel fusion toxin treatment, diphtheria toxin GM-CSF (DT-GMCSF) has been shown to selectively eliminate leukemic repopulating cells that are critical for the formation of AML. We previously showed that DT-GMCSF treatment of U937 cells, an AML cell line, causes activation of caspases and the induction of apoptosis. In this study we further investigate the mechanisms of cell death induced by DT-GMCSF and show that, in addition to the activation of caspase-dependent apoptosis, DT-GMCSF also kills AML cells by simultaneously activating caspase-independent necroptosis. These mechanisms depend on the ability of the targeted toxin to inhibit protein synthesis, and are not affected by the receptor that is targeted or the mechanism through which protein synthesis is blocked. We conclude that fusion toxin proteins may be effective for treating AML cells whether or not they are defective in apoptosis.

Muscarinic Receptors as Targets for Metronomic Therapy in Breast Cancer.

PubMed

Sales, María Elena

2016-01-01

It is actually known that acetylcholine works as a signaling molecule in non-neuronal cells and tissues, in addition to its neuronal function as neurotransmitter. It can act on two types of receptors nicotinic and muscarinic receptors (mAChRs). The latter belong to the G protein coupled receptor family and there are five subtypes genetically cloned. Their activation triggers classical and non-classical intracellular signals that could be linked to the proliferation of normal and/or transformed cells. The M3 subtype was identified in different types of tumors and its stimulation with agonists triggers cell proliferation, migration, invasion and metastasis. Our laboratory has extensively investigated the expression and function of mAChRs in breast tumors from animal and human origins. We found a profuse expression of mAChRs in breast tumors, but opposite to this, an absence of these receptors in normal breast cells and tissues. The stimulation of mAChRs with the cholinergic agonist carbachol for 20 h increased tumor cell death. Moreover, the combination of subthreshold concentrations of the agonist with paclitaxel potentiates cell death. The usage of low dose chemotherapy with short drug free intervals was named metronomic therapy and it has emerged as a novel regimen for cancer treatment with very low incidence of side effects. Our work and that of others indicate that mAChRs that are over-expressed in different types of tumor cells could be a useful target for metronomic therapy in cancer treatment.

Targeting the androgen receptor in triple-negative breast cancer.

PubMed

Gucalp, Ayca; Traina, Tiffany A

Triple-negative breast cancer represents approximately 15%-20% of all newly diagnosed breast cancers, but it accounts for a disproportionate number of breast cancer-related deaths each year. Owing to the lack of estrogen, progesterone, and human epidermal growth factor receptor 2 expression, patients with triple-negative breast cancer do not benefit from generally well-tolerated and effective therapies targeting the estrogen and human epidermal growth factor receptor 2 signaling pathways and are faced with an increased risk of disease progression and poorer overall survival. The heterogeneity of triple-negative breast cancer has been increasingly recognized and this may lead to therapeutic opportunities because of newly defined oncogenic drivers and targets. A subset of triple-negative breast tumors expresses the androgen receptor (AR) and this may benefit from treatments that inhibit the AR-signaling pathway. The first proof-of-concept trial established activity of the AR antagonist, bicalutamide, in patients with advanced AR+ triple-negative breast cancer. Since that time, evidence further supports the activity of other next-generation AR-targeted agents such as enzalutamide. Not unlike in estrogen receptor-positive breast cancer, mechanisms of resistance are being investigated and rationale exists for thoughtful, well-designed combination regimens such as AR antagonism with CDK4/6 pathway inhibitors or PI3K inhibitors. Furthermore, novel agents developed for the treatment of prostate cancer, which reduce androgen production such as abiraterone acetate and seviteronel, are being tested as well. This review summarizes the underlying biology of AR signaling in breast cancer development and the available clinical trial data for the use of anti-androgen therapy in the treatment of AR+ triple-negative breast cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Epidermal growth factor receptor and variant III targeted immunotherapy.

PubMed

Congdon, Kendra L; Gedeon, Patrick C; Suryadevara, Carter M; Caruso, Hillary G; Cooper, Laurence J N; Heimberger, Amy B; Sampson, John H

2014-10-01

Immunotherapeutic approaches to cancer have shown remarkable promise. A critical barrier to successfully executing such immune-mediated interventions is the selection of safe yet immunogenic targets. As patient deaths have occurred when tumor-associated antigens shared by normal tissue have been targeted by strong cellular immunotherapeutic platforms, route of delivery, target selection and the immune-mediated approach undertaken must work together to maximize efficacy with safety. Selected tumor-specific targets can spare potential toxicity to normal tissue; however, they are far less common than tumor-associated antigens and may not be present on all patients. In the context of immunotherapy for high-grade glioma, 2 of the most prominently studied antigens are the tumor-associated epidermal growth factor receptor and its tumor-specific genetic deletion variant III. In this review, we will summarize the immune-mediated strategies employed against these targets as well as the caveats particular to these approaches. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: A New Therapeutic Approach

PubMed Central

Muñoz, Miguel; Coveñas, Rafael

2015-01-01

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)—at high concentrations—is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert an antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC. PMID:26154566

A type III effector antagonizes death receptor signalling during bacterial gut infection.

PubMed

Pearson, Jaclyn S; Giogha, Cristina; Ong, Sze Ying; Kennedy, Catherine L; Kelly, Michelle; Robinson, Keith S; Lung, Tania Wong Fok; Mansell, Ashley; Riedmaier, Patrice; Oates, Clare V L; Zaid, Ali; Mühlen, Sabrina; Crepin, Valerie F; Marches, Olivier; Ang, Ching-Seng; Williamson, Nicholas A; O'Reilly, Lorraine A; Bankovacki, Aleksandra; Nachbur, Ueli; Infusini, Giuseppe; Webb, Andrew I; Silke, John; Strasser, Andreas; Frankel, Gad; Hartland, Elizabeth L

2013-09-12

Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonize the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic (EPEC and EHEC, respectively) Escherichia coli use a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonization and interfere with antimicrobial host responses. Here we report that the T3SS effector NleB1 from EPEC binds to host cell death-domain-containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death-inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death-receptor-induced apoptosis. This inhibition depended on the N-acetylglucosamine transferase activity of NleB1, which specifically modified Arg 117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing pathogens antagonize death-receptor-induced apoptosis of infected cells, thereby blocking a major antimicrobial host response.

A type III effector antagonises death receptor signalling during bacterial gut infection

PubMed Central

Pearson, Jaclyn S; Giogha, Cristina; Ong, Sze Ying; Kennedy, Catherine L; Kelly, Michelle; Robinson, Keith S; Wong, Tania; Mansell, Ashley; Riedmaier, Patrice; Oates, Clare VL; Zaid, Ali; Mühlen, Sabrina; Crepin, Valerie F; Marches, Olivier; Ang, Ching-Seng; Williamson, Nicholas A; O’Reilly, Lorraine A; Bankovacki, Aleksandra; Nachbur, Ueli; Infusini, Giuseppe; Webb, Andrew I; Silke, John; Strasser, Andreas; Frankel, Gad; Hartland, Elizabeth L

2013-01-01

Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonise the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic E. coli (EPEC and EHEC), utilise a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonisation and interfere with antimicrobial host responses 1-3. Here we report that the T3SS effector NleB1 from EPEC binds to host cell death domain containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death receptor induced apoptosis. This inhibition depended on the N-GlcNAc transferase activity of NleB1, which specifically modified Arg117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing (A/E) pathogens antagonise death receptor induced apoptosis of infected cells, thereby blocking a major antimicrobial host response. PMID:24025841

Fas cell surface death receptor controls hepatic lipid metabolism by regulating mitochondrial function.

PubMed

Item, Flurin; Wueest, Stephan; Lemos, Vera; Stein, Sokrates; Lucchini, Fabrizio C; Denzler, Rémy; Fisser, Muriel C; Challa, Tenagne D; Pirinen, Eija; Kim, Youngsoo; Hemmi, Silvio; Gulbins, Erich; Gross, Atan; O'Reilly, Lorraine A; Stoffel, Markus; Auwerx, Johan; Konrad, Daniel

2017-09-07

Nonalcoholic fatty liver disease is one of the most prevalent metabolic disorders and it tightly associates with obesity, type 2 diabetes, and cardiovascular disease. Reduced mitochondrial lipid oxidation contributes to hepatic fatty acid accumulation. Here, we show that the Fas cell surface death receptor (Fas/CD95/Apo-1) regulates hepatic mitochondrial metabolism. Hepatic Fas overexpression in chow-fed mice compromises fatty acid oxidation, mitochondrial respiration, and the abundance of mitochondrial respiratory complexes promoting hepatic lipid accumulation and insulin resistance. In line, hepatocyte-specific ablation of Fas improves mitochondrial function and ameliorates high-fat-diet-induced hepatic steatosis, glucose tolerance, and insulin resistance. Mechanistically, Fas impairs fatty acid oxidation via the BH3 interacting-domain death agonist (BID). Mice with genetic or pharmacological inhibition of BID are protected from Fas-mediated impairment of mitochondrial oxidation and hepatic steatosis. We suggest Fas as a potential novel therapeutic target to treat obesity-associated fatty liver and insulin resistance.Hepatic steatosis is a common disease closely associated with metabolic syndrome and insulin resistance. Here Item et al. show that Fas, a member of the TNF receptor superfamily, contributes to mitochondrial dysfunction, steatosis development, and insulin resistance under high fat diet.

Death receptor Fas (CD95) signaling in the central nervous system: tuning neuroplasticity?

PubMed

Reich, Arno; Spering, Christopher; Schulz, Jörg B

2008-09-01

For over a decade, neuroscientific research has focused on processes of apoptosis and its contribution to the pathophysiology of neurological diseases. In the central nervous system, the degree of intrinsic mitochondrial-mediated apoptotic signaling expresses a cell's individual metabolic stress, whereas activation of the extrinsic death receptor-induced cascade is regarded as a sign of imbalanced cellular networks. Under physiological conditions, most neurons possess death receptors without being sensitive to receptor-mediated apoptosis. This paradox raises two questions: what is the evolutionary advantage of expressing potentially harmful proteins? How is their signaling controlled? This review summarizes the functional relevance of FasL-Fas signaling--a quintessential death ligand/receptor system--in different neurological disease models ranging from traumatic, inflammatory and ischemic to neurodegenerative processes. Furthermore, it outlines alternative non-apoptotic Fas signaling, shedding new light on its neuroplastic capacity. Finally, receptor-proximal regulatory proteins are introduced and identified as potential protagonists of disease-modifying neurological therapies.

Hepatitis B virus-triggered autophagy targets TNFRSF10B/death receptor 5 for degradation to limit TNFSF10/TRAIL response.

PubMed

Shin, Gu-Choul; Kang, Hong Seok; Lee, Ah Ram; Kim, Kyun-Hwan

2016-12-01

Death receptors of TNFSF10/TRAIL (tumor necrosis factor superfamily member 10) contribute to immune surveillance against virus-infected or transformed cells by promoting apoptosis. Many viruses evade antiviral immunity by modulating TNFSF10 receptor signaling, leading to persistent infection. Here, we report that hepatitis B virus (HBV) X protein (HBx) restricts TNFSF10 receptor signaling via macroautophagy/autophagy-mediated degradation of TNFRSF10B/DR5, a TNFSF10 death receptor, and thus permits survival of virus-infected cells. We demonstrate that the expression of the TNFRSF10B protein is dramatically reduced both in liver tissues of chronic hepatitis B patients and in cell lines transfected with HBV or HBx. HBx-mediated downregulation of TNFRSF10B is caused by the lysosomal, but not proteasomal, degradation pathway. Immunoblotting analysis of LC3B and SQSTM1, and microscopy analysis of tandem-fluorescence-tagged LC3B revealed that HBx promotes complete autophagy. Inhibition of autophagy with a pharmacological inhibitor and LC3B knockdown revealed that HBx-induced autophagy is crucial for TNFRSF10B degradation. Immunoprecipitation and GST affinity isolation assays showed that HBx directly interacts with TNFRSF10B and recruits it to phagophores, the precursors to autophagosomes. We confirmed that autophagy activation is related to the downregulation of the TNFRSF10B protein in liver tissues of chronic hepatitis B patients. Inhibition of autophagy enhanced the susceptibility of HBx-infected hepatocytes to TNFSF10. These results identify the dual function of HBx in TNFRSF10B degradation: HBx plays a role as an autophagy receptor-like molecule, which promotes the association of TNFRSF10B with LC3B; HBx is also an autophagy inducer. Our data suggest a molecular mechanism for HBV evasion from TNFSF10-mediated antiviral immunity, which may contribute to chronic HBV infection.

Assembly of oligomeric death domain complexes during Toll receptor signaling.

PubMed

Moncrieffe, Martin C; Grossmann, J Günter; Gay, Nicholas J

2008-11-28

The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling.

Assembly of Oligomeric Death Domain Complexes during Toll Receptor Signaling*

PubMed Central

Moncrieffe, Martin C.; Grossmann, J. Günter; Gay, Nicholas J.

2008-01-01

The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling. PMID:18829464

P2X7 Receptor as a Therapeutic Target.

PubMed

De Marchi, Elena; Orioli, Elisa; Dal Ben, Diego; Adinolfi, Elena

2016-01-01

P2X7 receptor is an ATP-gated cation channel that upon agonist interaction leads to cellular influx of Na(+) and Ca(2+) and efflux of K(+). P2X7 is expressed by a wide variety of cells and its activation mediates a large number of biological processes like inflammation, neuromodulation, cell death or cell proliferation and it has been associated to related pathological conditions including infectious, inflammatory, autoimmune, neurological, and musculoskeletal disorders and, in the last years, to cancer. This chapter describes structural features of P2X7, chemical properties of its agonist, antagonist, and allosteric modulators and summarizes recent advances on P2X7 receptor as therapeutic target in the aforementioned diseases. We also give an overview on recent literature suggesting that P2X7 single-nucleotide polymorphisms could be exploited as diagnostic biomarkers for the development of tailored therapies. © 2016 Elsevier Inc. All rights reserved.

Targeting the TAM Receptors in Leukemia.

PubMed

Huey, Madeline G; Minson, Katherine A; Earp, H Shelton; DeRyckere, Deborah; Graham, Douglas K

2016-11-08

Targeted inhibition of members of the TAM (TYRO-3, AXL, MERTK) family of receptor tyrosine kinases has recently been investigated as a novel strategy for treatment of hematologic malignancies. The physiologic functions of the TAM receptors in innate immune control, natural killer (NK) cell differentiation, efferocytosis, clearance of apoptotic debris, and hemostasis have previously been described and more recent data implicate TAM kinases as important regulators of erythropoiesis and megakaryopoiesis. The TAM receptors are aberrantly or ectopically expressed in many hematologic malignancies including acute myeloid leukemia, B- and T-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and multiple myeloma. TAM receptors contribute to leukemic phenotypes through activation of pro-survival signaling pathways and interplay with other oncogenic proteins such as FLT3, LYN, and FGFR3. The TAM receptors also contribute to resistance to both cytotoxic chemotherapeutics and targeted agents, making them attractive therapeutic targets. A number of translational strategies for TAM inhibition are in development, including small molecule inhibitors, ligand traps, and monoclonal antibodies. Emerging areas of research include modulation of TAM receptors to enhance anti-tumor immunity, potential roles for TYRO-3 in leukemogenesis, and the function of the bone marrow microenvironment in mediating resistance to TAM inhibition.

An estrogen receptor targeted ruthenium complex as a two-photon photodynamic therapy agent for breast cancer cells.

PubMed

Zhao, Xueze; Li, Mingle; Sun, Wen; Fan, Jiangli; Du, Jianjun; Peng, Xiaojun

2018-06-21

In this study, we reported a tamoxifen modified Ru(ii) polypyridyl complex (Ru-tmxf) as an estrogen receptor (ER) targeted photosensitizer. Ru-tmxf displays enhanced cellular uptake and PDT efficiency toward breast cancer cells with high ER expression due to the specific targeting of tamoxifen to ER and finally localizes in lysosomes. Moreover, Ru-tmxf can be activated by two-photon excitation, generating 1O2 to damage lysosomes and result in cell death.

Targeting tachykinin receptors in neuroblastoma.

PubMed

Henssen, Anton G; Odersky, Andrea; Szymansky, Annabell; Seiler, Marleen; Althoff, Kristina; Beckers, Anneleen; Speleman, Frank; Schäfers, Simon; De Preter, Katleen; Astrahanseff, Kathy; Struck, Joachim; Schramm, Alexander; Eggert, Angelika; Bergmann, Andreas; Schulte, Johannes H

2017-01-03

Neuroblastoma is the most common extracranial tumor in children. Despite aggressive multimodal treatment, high-risk neuroblastoma remains a clinical challenge with survival rates below 50%. Adding targeted drugs to first-line therapy regimens is a promising approach to improve survival in these patients. TACR1 activation by substance P has been reported to be mitogenic in cancer cell lines. Tachykinin receptor (TACR1) antagonists are approved for clinical use as an antiemetic remedy since 2003. Tachykinin receptor inhibition has recently been shown to effectively reduce growth of several tumor types. Here, we report that neuroblastoma cell lines express TACR1, and that targeting TACR1 activity significantly reduced cell viability and induced apoptosis in neuroblastoma cell lines. Gene expression profiling revealed that TACR1 inhibition repressed E2F2 and induced TP53 signaling. Treating mice harboring established neuroblastoma xenograft tumors with Aprepitant also significantly reduced tumor burden. Thus, we provide evidence that the targeted inhibition of tachykinin receptor signaling shows therapeutic efficacy in preclinical models for high-risk neuroblastoma.

High cell surface death receptor expression determines type I versus type II signaling.

PubMed

Meng, Xue Wei; Peterson, Kevin L; Dai, Haiming; Schneider, Paula; Lee, Sun-Hee; Zhang, Jin-San; Koenig, Alexander; Bronk, Steve; Billadeau, Daniel D; Gores, Gregory J; Kaufmann, Scott H

2011-10-14

Previous studies have suggested that there are two signaling pathways leading from ligation of the Fas receptor to induction of apoptosis. Type I signaling involves Fas ligand-induced recruitment of large amounts of FADD (FAS-associated death domain protein) and procaspase 8, leading to direct activation of caspase 3, whereas type II signaling involves Bid-mediated mitochondrial perturbation to amplify a more modest death receptor-initiated signal. The biochemical basis for this dichotomy has previously been unclear. Here we show that type I cells have a longer half-life for Fas message and express higher amounts of cell surface Fas, explaining the increased recruitment of FADD and subsequent signaling. Moreover, we demonstrate that cells with type II Fas signaling (Jurkat or HCT-15) can signal through a type I pathway upon forced receptor overexpression and that shRNA-mediated Fas down-regulation converts cells with type I signaling (A498) to type II signaling. Importantly, the same cells can exhibit type I signaling for Fas and type II signaling for TRAIL (TNF-α-related apoptosis-inducing ligand), indicating that the choice of signaling pathway is related to the specific receptor, not some other cellular feature. Additional experiments revealed that up-regulation of cell surface death receptor 5 levels by treatment with 7-ethyl-10-hydroxy-camptothecin converted TRAIL signaling in HCT116 cells from type II to type I. Collectively, these results suggest that the type I/type II dichotomy reflects differences in cell surface death receptor expression.

Soluble TL1A is sufficient for activation of death receptor 3.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Füllsack, Simone; Kurz, Maria; Wajant, Harald; Ehrenschwender, Martin

2016-01-01

Death receptor 3 (DR3) is a typical member of the tumor necrosis factor receptor family, and was initially identified as a T-cell co-stimulatory molecule. However, further studies revealed a more complex and partly dichotomous role for DR3 and its ligand TL1A under (patho)physiological conditions. TL1A and DR3 are not only a driving force in the development of autoimmune and inflammatory diseases, but also play an important role in counteracting these processes through an increase in the number of regulatory T cells. Ligands of the tumor necrosis factor family typically occur in two forms, membrane-bound and soluble, that can differ strikingly with respect to their efficacy in activating their corresponding receptor(s). Ligand-based approaches to activate the TL1A-DR3 pathway therefore require understanding of the molecular prerequisites of TL1A-based DR3 activation. To date, this has not been addressed. Here, we show that recombinant soluble trimeric TL1A is fully sufficient to strongly activate DR3-associated pro- and anti-apoptotic signaling pathways. In contrast to the TRAIL death receptors, which are much better activated by soluble TRAIL upon secondary ligand oligomerization, but similarly to the death receptor tumor necrosis factor receptor 1, DR3 is efficiently activated by soluble TL1A trimers. Additionally, we have measured the affinity of TL1A-DR3 interaction in a cell-based system, and demonstrated TL1A-induced DR3 internalization. Identification of DR3 as a tumor necrosis factor receptor that responds to soluble ligand trimers without further oligomerization provides a basis for therapeutic exploitation of the TL1A-DR3 pathway. © 2015 FEBS.

REV-ERB and ROR nuclear receptors as drug targets

PubMed Central

Kojetin, Douglas J.; Burris, Thomas P.

2016-01-01

The nuclear receptors REV-ERB (consisting of REV-ERBα and REV-ERBβ) and retinoic acid receptor-related orphan receptors (RORs; consisting of RORα, RORβ and RORγ) are involved in many physiological processes, including regulation of metabolism, development and immunity as well as the circadian rhythm. The recent characterization of endogenous ligands for these former orphan nuclear receptors has stimulated the development of synthetic ligands and opened up the possibility of targeting these receptors to treat several diseases, including diabetes, atherosclerosis, autoimmunity and cancer. This Review focuses on the latest developments in ROR and REV-ERB pharmacology indicating that these nuclear receptors are druggable targets and that ligands targeting these receptors may be useful in the treatment of several disorders. PMID:24577401

Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

PubMed

Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

2018-02-14

Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

Death Receptor Expression on Blasts in AML Is Associated with Unfavorable Prognosis.

PubMed

Schmohl, Joerg Uwe; Nuebling, Tina; Wild, Julia; Jung, Johannes; Kroell, Tanja; Kanz, Lothar; Salih, Helmut R; Schmetzer, Helga

2015-07-01

Tumor necrosis factor (TNF) receptor family members play a key role in the regulation of biological functions such as differentiation, proliferation and apoptosis of various cell types. We studied co-expression profiles of death receptors from the TNF family [TNF-related apoptosis-inducing ligand receptor (TRAILR) 1 to 3, TNF receptor 1 (TNFR1) and FAS receptor (FAS)] on peripheral blood blasts from 46 patients with acute myeloid leukemia (AML) at first diagnosis by flow cytometry and correlated the obtained specific fluorescence indices (SFI) with morphological, cytogenetic and clinical parameters. We found that the expression of TRAILR2 and R3 was significantly increased in unfavorable risk groups, according to the National Comprehensive Cancer Network. Additionally, cut-off analyses for TRAILR2 and TNFR1 showed significantly shorter overall survival, earlier disease onset, higher proportions of cases with unfavorable prognosis and higher probability of relapse when SFIs were above the established cut-off. We demonstrate that high co-expression of death receptors on blasts is an independent predictor of poor prognosis in AML. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Schizophrenia, dissociative anaesthesia and near-death experience; three events meeting at the NMDA receptor.

PubMed

Bonta, Iván L

2004-01-01

The three events, viz. schizophrenia, dissociative anaesthesia and Near-Death Experience, despite their seemingly unrelated manifestation to each other, have nevertheless similar functional basis. All three events are linked to the glutamate sensitive N-methyl-D-aspartate (NMDA) receptor complex, which serves as their common functional denominator. Arguments and speculations are presented in favor of the view that, the three events might be considered as functional models of each other. Antagonism to the recognition NMDA-site of the receptor induces dissociative anaesthesia and precipitates Near-Death Experience. Agonist reinforcement at the modulatory glycine-site of the receptor counteracts negative symptoms of schizophrenia. Both types of challenges towards the receptor are compatible with a glutamate deficiency concept which underlies the meeting of the three events at the NMDA receptor.

In vitro photodynamic effects of scavenger receptor targeted-photoactivatable nanoagents on activated macrophages.

PubMed

Yi, Bong Gu; Park, Ok Kyu; Jeong, Myeong Seon; Kwon, Seung Hae; Jung, Jae In; Lee, Seongsoo; Ryoo, Sungwoo; Kim, Sung Eun; Kim, Jin Won; Moon, Won-Jin; Park, Kyeongsoon

2017-04-01

Scavenger receptors (SRs) expressed on the activated macrophages in inflammation sites have been considered as the most interesting and important target biomarker for targeted drug delivery, imaging and therapy. In the present study, we fabricated the scavenger receptor-A (SR-A) targeted-photoactivatable nanoagents (termed as Ce6/DS-DOCA) by entrapping chlorin e6 (Ce6) into the amphiphilic dextran sulfate-deoxycholic acid (DS-DOCA) conjugates via physically hydrophobic interactions. Insoluble Ce6 was easily encapsulated into DS-DOCA nanoparticles by a dialysis method and the loading efficiency was approximately 51.7%. The Ce6/DS-DOCA formed nano-sized self-assembled aggregates (28.8±5.6nm in diameter), confirmed by transmission electron microscope, UV/Vis and fluorescence spectrophotometer. The Ce6/DS-DOCA nanoagents could generate highly reactive singlet oxygen under laser irradiation. Also, in vitro studies showed that they were more specifically taken up by lipopolysaccharide (LPS)-induced activated macrophages (RAW 264.7) via a SR-A-mediated endocytosis, relative to by non-activated macrophages, and notably induced cell death of activated macrophages under laser irradiation. Therefore, SR-A targetable and photoactivatable Ce6/DS-DOCA nanoagents with more selective targeting to the activated macrophages will have great potential for treatment of inflammatory diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Activation of aryl hydrocarbon receptor reduces carbendazim-induced cell death

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Kuo-Liang

aryl hydrocarbon receptor (AhR). • Carbendazim induced the expression of cytochrome P450 (CYP) 1A1, an AhR-targeted gene. • Carbendazim is an AhR agonist. • The activated AhR decreased carbendazim-induced cell toxicity and death.« less

Characterization of the Interactions between Calmodulin and Death Receptor 5 in Triple-negative and Estrogen Receptor-positive Breast Cancer Cells

PubMed Central

Fancy, Romone M.; Wang, Lingyun; Zeng, Qinghua; Wang, Hong; Zhou, Tong; Buchsbaum, Donald J.; Song, Yuhua

2016-01-01

Activation of death receptor-5 (DR5) leads to the formation of death inducing signaling complex (DISC) for apoptotic signaling. Targeting DR5 to induce breast cancer apoptosis is a promising strategy to circumvent drug resistance and present a target for breast cancer treatment. Calmodulin (CaM) has been shown to regulate DR5-mediated apoptotic signaling, however, its mechanism remains unknown. In this study, we characterized CaM and DR5 interactions in breast cancer cells with integrated experimental and computational approaches. Results show that CaM directly binds to DR5 in a calcium dependent manner in breast cancer cells. The direct interaction of CaM with DR5 is localized at DR5 death domain. We have predicted and verified the CaM-binding site in DR5 being 354WEPLMRKLGL363 that is located at the α2 helix and the loop between α2 helix and α3 helix of DR5 DD. The residues of Trp-354, Arg-359, Glu-355, Leu-363, and Glu-367 in DR5 death domain that are important for DR5 recruitment of FADD and caspase-8 for DISC formation to signal apoptosis also play an important role for CaM-DR5 binding. The changed electrostatic potential distribution in the CaM-binding site in DR5 DD by the point mutations of W354A, E355K, R359A, L363N, or E367K in DR5 DD could directly contribute to the experimentally observed decreased CaM-DR5 binding by the point mutations of the key residues in DR5 DD. Results from this study provide a key step for the further investigation of the role of CaM-DR5 binding in DR5-mediated DISC formation for apoptosis in breast cancer cells. PMID:27129269

Targeting xenobiotic receptors PXR and CAR in human diseases

PubMed Central

Banerjee, Monimoy; Robbins, Delira; Chen, Taosheng

2014-01-01

Nuclear receptors such as the pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are xenobiotic receptors regulating not only drug metabolism and disposition but also various human diseases such as cancer, diabetes, inflammatory disease, metabolic disease and liver diseases, suggesting that PXR and CAR are promising targets for drug discovery. Consequently, there is an urgent need to discover and develop small molecules that target these PXR- and/or CAR-mediated human-disease-related pathways for relevant therapeutic applications. This review proposes approaches to target PXR and CAR, either individually or simultaneously, in the context of various human diseases, taking into consideration the structural differences between PXR and CAR. PMID:25463033

Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

PubMed Central

Lee, Won Sup; Jung, Ji Hyun; Panchanathan, Radha; Yun, Jeong Won; Kim, Dong Hoon; Kim, Hye Jung; Kim, Gon Sup; Ryu, Chung Ho; Shin, Sung Chul; Hong, Soon Chan; Choi, Yung Hyun; Jung, Jin-Myung

2017-01-01

Background Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells. Methods Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting. Results UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway. Conclusions UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer. PMID:28382282

The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy.

PubMed

Alves, Mariana; Beamer, Edward; Engel, Tobias

2018-01-01

Epilepsy encompasses a heterogeneous group of neurological syndromes which are characterized by recurrent seizures affecting over 60 million people worldwide. Current anti-epileptic drugs (AEDs) are mainly designed to target ion channels and/or GABA or glutamate receptors. Despite recent advances in drug development, however, pharmacoresistance in epilepsy remains as high as 30%, suggesting the need for the development of new AEDs with a non-classical mechanism of action. Neuroinflammation is increasingly recognized as one of the key players in seizure generation and in the maintenance of the epileptic phenotype. Consequently, targeting signaling molecules involved in inflammatory processes may represent new avenues to improve treatment in epilepsy. Nucleotides such as adenosine-5'-triphosphate (ATP) and uridine-5'-triphosphate (UTP) are released in the brain into the extracellular space during pathological conditions such as increased neuronal firing or cell death. Once released, these nucleotides bind to and activate specific purinergic receptors termed P2 receptors where they mediate the release of gliotransmitters and drive neuronal hyperexcitation and neuroinflammatory processes. This includes the fast acting ionotropic P2X channels and slower-acting G-protein-coupled P2Y receptors. While the expression and function of P2X receptors has been well-established in experimental models of epilepsy, emerging evidence is now also suggesting a prominent role for the P2Y receptor subfamily in seizure generation and the maintenance of epilepsy. In this review we discuss data supporting a role for the P2Y receptor family in epilepsy and the most recent finding demonstrating their involvement during seizure-induced pathology and in epilepsy.

Programmed Cell Death-1/Programmed Death-ligand 1 Pathway: A New Target for Sepsis.

PubMed

Liu, Qiang; Li, Chun-Sheng

2017-04-20

Sepsis remains a leading cause of death in many Intensive Care Units worldwide. Immunosuppression has been a primary focus of sepsis research as a key pathophysiological mechanism. Given the important role of the negative costimulatory molecules programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in the occurrence of immunosuppression during sepsis, we reviewed literatures related to the PD-1/PD-L1 pathway to examine its potential as a new target for sepsis treatment. Studies of the association between PD-1/PD-L1 and sepsis published up to January 31, 2017, were obtained by searching the PubMed database. English language studies, including those based on animal models, clinical research, and reviews, with data related to PD-1/PD-L1 and sepsis, were evaluated. Immunomodulatory therapeutics could reverse the deactivation of immune cells caused by sepsis and restore immune cell activation and function. Blockade of the PD-1/PD-L1 pathway could reduce the exhaustion of T-cells and enhance the proliferation and activation of T-cells. The anti-PD-1/PD-L1 pathway shows promise as a new target for sepsis treatment. This review provides a basis for clinical trials and future studies aimed at revaluating the efficacy and safety of this targeted approach.

Targeted anticancer therapy: overexpressed receptors and nanotechnology.

PubMed

Akhtar, Mohd Javed; Ahamed, Maqusood; Alhadlaq, Hisham A; Alrokayan, Salman A; Kumar, Sudhir

2014-09-25

Targeted delivery of anticancer drugs to cancer cells and tissues is a promising field due to its potential to spare unaffected cells and tissues, but it has been a major challenge to achieve success in these therapeutic approaches. Several innovative approaches to targeted drug delivery have been devised based on available knowledge in cancer biology and on technological advancements. To achieve the desired selectivity of drug delivery, nanotechnology has enabled researchers to design nanoparticles (NPs) to incorporate anticancer drugs and act as nanocarriers. Recently, many receptor molecules known to be overexpressed in cancer have been explored as docking sites for the targeting of anticancer drugs. In principle, anticancer drugs can be concentrated specifically in cancer cells and tissues by conjugating drug-containing nanocarriers with ligands against these receptors. Several mechanisms can be employed to induce triggered drug release in response to either endogenous trigger or exogenous trigger so that the anticancer drug is only released upon reaching and preferentially accumulating in the tumor tissue. This review focuses on overexpressed receptors exploited in targeting drugs to cancerous tissues and the tumor microenvironment. We briefly evaluate the structure and function of these receptor molecules, emphasizing the elegant mechanisms by which certain characteristics of cancer can be exploited in cancer treatment. After this discussion of receptors, we review their respective ligands and then the anticancer drugs delivered by nanotechnology in preclinical models of cancer. Ligand-functionalized nanocarriers have delivered significantly higher amounts of anticancer drugs in many in vitro and in vivo models of cancer compared to cancer models lacking such receptors or drug carrying nanocarriers devoid of ligand. This increased concentration of anticancer drug in the tumor site enabled by nanotechnology could have a major impact on the efficiency of cancer

Tryptophol induces death receptor (DR) 5-mediated apoptosis in U937 cells.

PubMed

Inagaki, Shyuichiro; Morimura, Shigeru; Tang, Yueqin; Akutagawa, Hiroshi; Kida, Kenji

2007-08-01

Tryptophol is a natural component isolated from vinegar produced from the boiled extract of black soybean. We have reported that tryptophol induces apoptosis in U937 cells via activation of caspase-8 followed by caspase-3. Tryptophol, however, did not affect human peripheral blood lymphocytes (PBL). In this study, we found that tryptophol enhances formation of a death-inducing signaling complex including death receptor (DR) 5. Cell viability and induction of apoptosis by tryptophol was reduced by transfection with decoy receptor (DcR) 1. These results indicate that tryptophol induces apoptosis through DR5 and that the resistance of PBL to tryptophol-induced apoptosis might be due to competition from DcR1.

TGFbeta type II receptor signaling controls Schwann cell death and proliferation in developing nerves.

PubMed

D'Antonio, Maurizio; Droggiti, Anna; Feltri, M Laura; Roes, Jürgen; Wrabetz, Lawrence; Mirsky, Rhona; Jessen, Kristján R

2006-08-16

During development, Schwann cell numbers are precisely adjusted to match the number of axons. It is essentially unknown which growth factors or receptors carry out this important control in vivo. Here, we tested whether the type II transforming growth factor (TGF) beta receptor has a role in this process. We generated a conditional knock-out mouse in which the type II TGFbeta receptor is specifically ablated only in Schwann cells. Inactivation of the receptor, evident at least from embryonic day 18, resulted in suppressed Schwann cell death in normally developing and injured nerves. Notably, the mutants also showed a strong reduction in Schwann cell proliferation. Consequently, Schwann cell numbers in wild-type and mutant nerves remained similar. Lack of TGFbeta signaling did not appear to affect other processes in which TGFbeta had been implicated previously, including myelination and response of adult nerves to injury. This is the first in vivo evidence for a growth factor receptor involved in promoting Schwann cell division during development and the first genetic evidence for a receptor that controls normal developmental Schwann cell death.

Delta-opioid receptors as targets for migraine therapy.

PubMed

Charles, Andrew; Pradhan, Amynah A

2016-06-01

The purpose of this review is to contrast the properties of the δ-opioid receptor with those of the μ-opioid receptor, which is the primary target of most currently available opioid analgesics. We also discuss preclinical evidence that indicates the potential efficacy of δ-opioid receptor agonists as migraine therapy. The use of currently available opioid analgesics is highly problematic for patients with migraine. Delta-opioid receptors have key differences from μ receptors; these differences make the δ receptor an attractive therapeutic target for migraine. Delta-opioid receptors are expressed in both the peripheral and central nervous system in anatomical regions and cell types that are believed to play a role in migraine. Delta-receptor agonists have also shown promising effects in multiple migraine models, including nitroglycerin evoked hyperalgesia and conditioned place aversion, and cortical spreading depression. Evidence from animal models indicates that activation of δ receptors is less likely to cause tolerance and dependence, and less likely to cause hyperalgesia. In addition, δ receptors may have antidepressant and anxiolytic properties that are distinct from those of μ receptors. In human studies investigating other conditions, δ-receptor agonists have been generally safe and well tolerated. Delta-opioid receptor agonists have promising potential as acute and/or preventive migraine therapies, without the problems associated with currently used opioid analgesics.

Androgen Receptor: A Complex Therapeutic Target for Breast Cancer

PubMed Central

Narayanan, Ramesh; Dalton, James T.

2016-01-01

Molecular and histopathological profiling have classified breast cancer into multiple sub-types empowering precision treatment. Although estrogen receptor (ER) and human epidermal growth factor receptor (HER2) are the mainstay therapeutic targets in breast cancer, the androgen receptor (AR) is evolving as a molecular target for cancers that have developed resistance to conventional treatments. The high expression of AR in breast cancer and recent discovery and development of new nonsteroidal drugs targeting the AR provide a strong rationale for exploring it again as a therapeutic target in this disease. Ironically, both nonsteroidal agonists and antagonists for the AR are undergoing clinical trials, making AR a complicated target to understand in breast cancer. This review provides a detailed account of AR’s therapeutic role in breast cancer. PMID:27918430

P2X receptors as targets for the treatment of status epilepticus

PubMed Central

Henshall, David C.; Diaz-Hernandez, Miguel; Miras-Portugal, M. Teresa; Engel, Tobias

2013-01-01

Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA) transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4, and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection. PMID:24324404

P2X receptors as targets for the treatment of status epilepticus.

PubMed

Henshall, David C; Diaz-Hernandez, Miguel; Miras-Portugal, M Teresa; Engel, Tobias

2013-11-26

Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA) transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4, and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection.

Sigma receptors as potential therapeutic targets for neuroprotection.

PubMed

Nguyen, Linda; Kaushal, Nidhi; Robson, Matthew J; Matsumoto, Rae R

2014-11-15

Sigma receptors comprise a unique family of proteins that have been implicated in the pathophysiology and treatment of many central nervous system disorders, consistent with their high level of expression in the brain and spinal cord. Mounting evidence indicate that targeting sigma receptors may be particularly beneficial in a number of neurodegenerative conditions including Alzheimer׳s disease, Parkinson׳s disease, stroke, methamphetamine neurotoxicity, Huntington׳s disease, amyotrophic lateral sclerosis, and retinal degeneration. In this perspective, a brief overview is given on sigma receptors, followed by a focus on common mechanisms of neurodegeneration that appear amenable to modulation by sigma receptor ligands to convey neuroprotective effects and/or restorative functions. Within each of the major mechanisms discussed herein, the neuroprotective effects of sigma ligands are summarized, and when known, the specific sigma receptor subtype(s) involved are identified. Together, the literature suggests sigma receptors may provide a novel target for combatting neurodegenerative diseases through both neuronal and glial mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

M1 muscarinic receptor activation mediates cell death in M1-HEK293 cells.

PubMed

Graham, E Scott; Woo, Kerhan K; Aalderink, Miranda; Fry, Sandie; Greenwood, Jeffrey M; Glass, Michelle; Dragunow, Mike

2013-01-01

HEK293 cells have been used extensively to generate stable cell lines to study G protein-coupled receptors, such as muscarinic acetylcholine receptors (mAChRs). The activation of M1 mAChRs in various cell types in vitro has been shown to be protective. To further investigate M1 mAChR-mediated cell survival, we generated stable HEK293 cell-lines expressing the human M1 mAChR. M1 mAChRs were efficiently expressed at the cell surface and efficiently internalised within 1 h by carbachol. Carbachol also induced early signalling cascades similar to previous reports. Thus, ectopically expressed M1 receptors behaved in a similar fashion to the native receptor over short time periods of analysis. However, substantial cell death was observed in HEK293-M1 cells within 24 h after carbachol application. Death was only observed in HEK cells expressing M1 receptors and fully blocked by M1 antagonists. M1 mAChR-stimulation mediated prolonged activation of the MEK-ERK pathway and resulted in prolonged induction of the transcription factor EGR-1 (>24 h). Blockade of ERK signalling with U0126 did not reduce M1 mAChR-mediated cell-death significantly but inhibited the acute induction of EGR-1. We investigated the time-course of cell death using time-lapse microscopy and xCELLigence technology. Both revealed the M1 mAChR cytotoxicity occurs within several hours of M1 activation. The xCELLigence assay also confirmed that the ERK pathway was not involved in cell-death. Interestingly, the MEK blocker did reduce carbachol-mediated cleaved caspase 3 expression in HEK293-M1 cells. The HEK293 cell line is a widely used pharmacological tool for studying G-protein coupled receptors, including mAChRs. Our results highlight the importance of investigating the longer term fate of these cells in short term signalling studies. Identifying how and why activation of the M1 mAChR signals apoptosis in these cells may lead to a better understanding of how mAChRs regulate cell-fate decisions.

Poly(ADP-ribose) polymerase inhibitors sensitize cancer cells to death receptor-mediated apoptosis by enhancing death receptor expression.

PubMed

Meng, X Wei; Koh, Brian D; Zhang, Jin-San; Flatten, Karen S; Schneider, Paula A; Billadeau, Daniel D; Hess, Allan D; Smith, B Douglas; Karp, Judith E; Kaufmann, Scott H

2014-07-25

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation.

Poly(ADP-ribose) Polymerase Inhibitors Sensitize Cancer Cells to Death Receptor-mediated Apoptosis by Enhancing Death Receptor Expression*

PubMed Central

Meng, X. Wei; Koh, Brian D.; Zhang, Jin-San; Flatten, Karen S.; Schneider, Paula A.; Billadeau, Daniel D.; Hess, Allan D.; Smith, B. Douglas; Karp, Judith E.; Kaufmann, Scott H.

2014-01-01

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation. PMID:24895135

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor.

PubMed

Mavlyutov, Timur A; Nickells, Robert W; Guo, Lian-Wang

2011-04-26

The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1(-/-)) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1(-/-) mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1(-/-), demonstrating a significant difference between the wild-type and the Sigmar1(-/-) in crush-induced ganglion cell loss. Our data indicated faster retinal ganglion cell death in Sigmar1(-/-) than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma.

Epidermal Growth Factor Receptor Tyrosine Kinase: A Potential Target in Treatment of Non-Small-Cell Lung Carcinoma.

PubMed

Prabhu, Venugopal Vinod; Devaraj, Niranjali

2017-01-01

Lung cancer is responsible for 1.6 million deaths. Approximately 80%-85% of lung cancers are of the non-small-cell variety, which includes squamous cell carcinoma, adenocarcinoma, and large-cell carcinoma. Knowing the stage of cancer progression is a requisite for determining which management approach-surgery, chemotherapy, radiotherapy, and/or immunotherapy-is optimal. Targeted therapeutic approaches with antiangiogenic monoclonal antibodies or tyrosine kinase inhibitors are one option if tumors harbor oncogene mutations. Another, newer approach is directed against cancer-specific molecules and signaling pathways and thus has more limited nonspecific toxicities. This approach targets the epidermal growth factor receptor (EGFR, HER-1/ErbB1), a receptor tyrosine kinase of the ErbB family, which consists of four closely related receptors: HER-1/ErbB1, HER-2/neu/ErbB2, HER-3/ErbB3, and HER-4/ErbB4. Because EGFR is expressed at high levels on the surface of some cancer cells, it has been recognized as an effective anticancer target. EGFR-targeted therapies include monoclonal antibodies (mAbs) and small-molecule tyrosine kinase inhibitors. Tyrosine kinases are an especially important target because they play an important role in the modulation of growth factor signaling. This review highlights various classes of synthetically derived molecules that have been reported in the last few years as potential EGFR-TK inhibitors (TKIs) and their targeted therapies in NSCLC, along with effective strategies for overcoming EGFR-TKI resistance and efforts to develop a novel potent EGFR-TKI as an efficient target of NSCLC treatment in the foreseeable future.

GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis

PubMed Central

Wrzaczek, Michael; Vainonen, Julia P; Stael, Simon; Tsiatsiani, Liana; Help-Rinta-Rahko, Hanna; Gauthier, Adrien; Kaufholdt, David; Bollhöner, Benjamin; Lamminmäki, Airi; Staes, An; Gevaert, Kris; Tuominen, Hannele; Van Breusegem, Frank; Helariutta, Ykä; Kangasjärvi, Jaakko

2015-01-01

Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor. PMID:25398910

GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis.

PubMed

Wrzaczek, Michael; Vainonen, Julia P; Stael, Simon; Tsiatsiani, Liana; Help-Rinta-Rahko, Hanna; Gauthier, Adrien; Kaufholdt, David; Bollhöner, Benjamin; Lamminmäki, Airi; Staes, An; Gevaert, Kris; Tuominen, Hannele; Van Breusegem, Frank; Helariutta, Ykä; Kangasjärvi, Jaakko

2015-01-02

Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor. © 2014 The Authors.

Cigarette smoke-induced cell death of a spermatocyte cell line can be prevented by inactivating the Aryl hydrocarbon receptor

PubMed Central

Esakky, P; Hansen, D A; Drury, A M; Cusumano, A; Moley, K H

2015-01-01

Cigarette smoke exposure causes germ cell death during spermatogenesis. Our earlier studies demonstrated that cigarette smoke condensate (CSC) causes spermatocyte cell death in vivo and growth arrest of the mouse spermatocyte cell line (GC-2spd(ts)) in vitro via the aryl hydrocarbon receptor (AHR). We hypothesize here that inactivation of AHR could prevent the CSC-induced cell death in spermatocytes. We demonstrate that CSC exposure generates oxidative stress, which differentially regulates mitochondrial apoptosis in GC-2spd(ts) and wild type (WT) and AHR knockout (AHR-KO) mouse embryonic fibroblasts (MEFs). SiRNA-mediated silencing of Ahr augments the extent of CSC-mediated cellular damage while complementing the AHR-knockout condition. Pharmacological inhibition using the AHR-antagonist (CH223191) modulates the CSC-altered expression of apoptotic proteins and significantly abrogates DNA fragmentation though the cleavage of PARP appears AHR independent. Pretreatment with CH223191 at concentrations above 50 μM significantly prevents the CSC-induced activation of caspase-3/7 and externalization of phosphatidylserine in the plasma membrane. However, MAPK inhibitors alone or together with CH223191 could not prevent the membrane damage upon CSC addition and the caspase-3/7 activation and membrane damage in AHR-deficient MEF indicates the interplay of multiple cell signaling and cytoprotective ability of AHR. Thus the data obtained on one hand signifies the protective role of AHR in maintaining normal cellular homeostasis and the other, could be a potential prophylactic therapeutic target to promote cell survival and growth under cigarette smoke exposed environment by receptor antagonism via CH223191-like mechanism. Antagonist-mediated inactivation of the aryl hydrocarbon receptor blocks downstream events leading to cigarette smoke-induced cell death of a spermatocyte cell line. PMID:27551479

A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

PubMed

Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

2014-12-01

Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Research Resource: Global Identification of Estrogen Receptor β Target Genes in Triple Negative Breast Cancer Cells

PubMed Central

Shanle, Erin K.; Zhao, Zibo; Hawse, John; Wisinski, Kari; Keles, Sunduz; Yuan, Ming

2013-01-01

Breast cancers that are negative for estrogen receptor α (ERα), progesterone receptor, and human epidermal growth factor receptor 2 are known as triple-negative breast cancers (TNBC). TNBCs are associated with an overall poor prognosis because they lack expression of therapeutic targets like ERα and are biologically more aggressive. A second estrogen receptor, ERβ, has been found to be expressed in 50% to 90% of ERα-negative breast cancers, and ERβ expression in TNBCs has been shown to correlate with improved disease-free survival and good prognosis. To elucidate the role of ERβ in regulating gene expression and cell proliferation in TNBC cells, the TNBC cell line MDA-MB-468 was engineered with inducible expression of full-length ERβ. In culture, ERβ expression inhibited cell growth by inducing a G1 cell cycle arrest, which was further enhanced by 17β-estradiol treatment. In xenografts, ERβ expression also inhibited tumor formation and growth, and 17β-estradiol treatment resulted in rapid tumor regression. Furthermore, genomic RNA sequencing identified both ligand-dependent and -independent ERβ target genes, some of which were also regulated by ERβ in other TNBC cell lines and correlated with ERβ expression in a cohort of TNBCs from the Cancer Genome Atlas Network. ERβ target genes were enriched in genes that regulate cell death and survival, cell movement, cell development, and growth and proliferation, as well as genes involved in the Wnt/β-catenin and the G1/S cell cycle phase checkpoint pathways. In addition to confirming the anti-proliferative effects of ERβ in TNBC cells, these data provide a comprehensive resource of ERβ target genes and suggest that ERβ may be targeted with ligands that can stimulate its growth inhibitory effects. PMID:23979844

Development of contrast agents targeted to macrophage scavenger receptors for MRI of vascular inflammation

PubMed Central

Gustafsson, Björn; Youens, Susan; Louie, Angelique Y.

2008-01-01

Atherosclerosis is a leading cause of death in the U.S. Because there is a potential to prevent coronary and arterial diseases through early diagnosis, there is a need for methods to image arteries in the sub-clinical stage as well as clinical stage using various non-invasive techniques, including Magnetic Resonance Imaging (MRI). We describe a development of a novel MRI contrast agent targeted to plaques that will allow imaging of lesion formation. The contrast agent is directed to macrophages, one of the earliest components of developing plaques. Macrophages are labeled through the macrophage scavenger receptor A, a macrophage specific cell surface protein, using an MRI contrast agent derived from scavenger receptor ligands. We have synthesized and characterized these contrast agents with a range of relaxivities. In vitro studies show that the targeted contrast agent accumulates in macrophages and solution studies indicate that micromolar concentrations are sufficient to produce contrast in an MR image. Cell toxicity and initial biodistribution studies indicate low toxicity, no detectable retention in normal blood vessels, and rapid clearance from blood. The promising performance of this contrast agent targeted towards vascular inflammation opens doors to tracking of other inflammatory diseases such as tumor immunotherapy and transplant acceptance using MRI. PMID:16536488

Gefitinib enhances human colon cancer cells to TRAIL-induced apoptosis of via autophagy- and JNK-mediated death receptors upregulation.

PubMed

Chen, Lei; Meng, Yue; Guo, Xiaoqing; Sheng, Xiaotong; Tai, Guihua; Zhang, Fenglei; Cheng, Hairong; Zhou, Yifa

2016-11-01

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a potent cancer cell-specific apoptosis-inducing cytokine with little toxicity to most normal cells. Here, we report that gefitinib and TRAIL in combination produce a potent synergistic effect on TRAIL-sensitive human colon cancer HCT116 cells and an additive effect on TRAIL-resistant HT-29 cells. Interestingly, gefitinib increases the expression of cell surface receptors DR4 and DR5, possibly explaining the synergistic effect. Knockdown of DR4 and DR5 by siRNA significantly decreases gefitinib- and TRAIL-mediated cell apoptosis, supporting this idea. Because the inhibition of gefitinib-induced autophagy by 3-MA significantly decreases DR4 and DR5 upregulation, as well as reduces gefitinib- and TRAIL-induced apoptosis, we conclude that death receptor upregulation is autophagy mediated. Furthermore, our results indicate that death receptor expression may also be regulated by JNK activation, because pre-treatment of cells with JNK inhibitor SP600125 significantly decreases gefitinib-induced death receptor upregulation. Interestingly, SP600125 also inhibits the expression CHOP, yet CHOP has no impact on death receptor expressions. We also find here that phosphorylation of Akt and ERK might also be required for TRAIL sensitization. In summary, our results indicate that gefitinib effectively enhances TRAIL-induced apoptosis, likely via autophagy and JNK- mediated death receptor expression and phosphorylation of Akt and ERK.

The engulfment receptor Draper is required for autophagy during cell death.

PubMed

McPhee, Christina K; Baehrecke, Eric H

2010-11-01

Autophagy is a process to degrade and recycle cytoplasmic contents. Autophagy is required for survival in response to starvation, but has also been associated with cell death. How autophagy functions during cell survival in some contexts and cell death in others is unknown. Drosophila larval salivary glands undergo programmed cell death requiring autophagy genes, and are cleared in the absence of known phagocytosis. Recently, we demonstrated that Draper (Drpr), the Drosophila homolog of C. elegans engulfment receptor CED-1, is required for autophagy induction: during cell death, but not during cell survival. drpr mutants fail to clear salivary glands. drpr knockdown in salivary glands prevents the induction of autophagy, and Atg1 misexpression in drpr null mutants suppresses salivary gland persistence. Surprisingly, drpr knockdown cell-autonomously prevents autophagy induction in dying salivary gland cells, but not in larval fat body cells following starvation. This is the first engulfment factor shown to function in cellular self-clearance, and the first report of a cell-death-specific autophagy regulator.

Targeting Nuclear Receptors with Marine Natural Products

PubMed Central

Yang, Chunyan; Li, Qianrong; Li, Yong

2014-01-01

Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators. PMID:24473166

Receptor-Mediated Drug Delivery Systems Targeting to Glioma

PubMed Central

Wang, Shanshan; Meng, Ying; Li, Chengyi; Qian, Min; Huang, Rongqin

2015-01-01

Glioma has been considered to be the most frequent primary tumor within the central nervous system (CNS). The complexity of glioma, especially the existence of the blood-brain barrier (BBB), makes the survival and prognosis of glioma remain poor even after a standard treatment based on surgery, radiotherapy, and chemotherapy. This provides a rationale for the development of some novel therapeutic strategies. Among them, receptor-mediated drug delivery is a specific pattern taking advantage of differential expression of receptors between tumors and normal tissues. The strategy can actively transport drugs, such as small molecular drugs, gene medicines, and therapeutic proteins to glioma while minimizing adverse reactions. This review will summarize recent progress on receptor-mediated drug delivery systems targeting to glioma, and conclude the challenges and prospects of receptor-mediated glioma-targeted therapy for future applications. PMID:28344260

Group IIA secretory phospholipase A2 (GIIA) mediates apoptotic death during NMDA receptor activation in rat primary cortical neurons.

PubMed

Chiricozzi, Elena; Fernandez-Fernandez, Seila; Nardicchi, Vincenza; Almeida, Angeles; Bolaños, Juan Pedro; Goracci, Gianfrancesco

2010-03-01

Phospholipases A(2) (PLA(2)) participate in neuronal death signalling pathways because of their ability to release lipid mediators, although the contribution of each isoform and mechanism of neurotoxicity are still elusive. Using a novel fluorogenic method to assess changes in a PLA(2) activity by flow cytometry, here we show that the group IIA secretory phospholipase A(2) isoform (GIIA) was specifically activated in cortical neurons following stimulation of N-methyl-d-aspartate glutamate receptor subtype (NMDAR). For activation, GIIA required Ca(2+) and reactive oxygen/nitrogen species, and inhibition of its activity fully prevented NMDAR-mediated neuronal apoptotic death. Superoxide, nitric oxide or peroxynitrite donors stimulated GIIA activity, which mediated neuronal death. Intriguingly, we also found that GIIA activity induced mitochondrial superoxide production after NMDAR stimulation. These results reveal a novel role for GIIA in excitotoxicity both as target and producer of superoxide in a positive-loop of activation that may contribute to the propagation of neurodegeneration.

Senescent cells re-engineered to express soluble programmed death receptor-1 for inhibiting programmed death receptor-1/programmed death ligand-1 as a vaccination approach against breast cancer.

PubMed

Chen, Zehong; Hu, Kang; Feng, Lieting; Su, Ruxiong; Lai, Nan; Yang, Zike; Kang, Shijun

2018-06-01

Various types of vaccines have been proposed as approaches for prevention or delay of the onset of cancer by boosting the endogenous immune system. We previously developed a senescent-cell-based vaccine, induced by radiation and veliparib, as a preventive and therapeutic tool against triple-negative breast cancer. However, the programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) pathway was found to play an important role in vaccine failure. Hence, we further developed soluble programmed death receptor-1 (sPD1)-expressing senescent cells to overcome PD-L1/PD-1-mediated immune suppression while vaccinating to promote dendritic cell (DC) maturity, thereby amplifying T-cell activation. In the present study, sPD1-expressing senescent cells showed a particularly active status characterized by growth arrest and modified immunostimulatory cytokine secretion in vitro. As expected, sPD1-expressing senescent tumor cell vaccine (STCV/sPD-1) treatment attracted more mature DC and fewer exhausted-PD1 + T cells in vivo. During the course of the vaccine studies, we observed greater safety and efficacy for STCV/sPD-1 than for control treatments. STCV/sPD-1 pre-injections provided complete protection from 4T1 tumor challenge in mice. Additionally, the in vivo therapeutic study of mice with s.c. 4T1 tumor showed that STCV/sPD-1 vaccination delayed tumorigenesis and suppressed tumor progression at early stages. These results showed that STCV/sPD-1 effectively induced a strong antitumor immune response against cancer and suggested that it might be a potential strategy for TNBC prevention. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

α-Hispanolol sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis via death receptor up-regulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mota, Alba, E-mail: amota@iib.uam.es; Jiménez-Garcia, Lidia, E-mail: ljimenez@isciii.es; Herránz, Sandra, E-mail: sherranz@isciii.es

Hispanolone derivatives have been previously described as anti-inflammatory and antitumoral agents. However, their effects on overcoming Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance remain to be elucidated. In this study, we analyzed the cytotoxic effects of the synthetic hispanolone derivative α-hispanolol (α-H) in several tumor cell lines, and we evaluated the induction of apoptosis, as well as the TRAIL-sensitizing potential of α-H in the hepatocellular carcinoma cell line HepG2. Our data show that α-H decreased cell viability in a dose-dependent manner in HeLa, MDA-MB231, U87 and HepG2 cell lines, with a more prominent effect in HepG2 cells. Interestingly, α-H hadmore » no effect on non-tumoral cells. α-H induced activation of caspase-8 and caspase-9 and also increased levels of the proapoptotic protein Bax, decreasing antiapoptotic proteins (Bcl-2, X-IAP and IAP-1) in HepG2 cells. Specific inhibition of caspase-8 abrogated the cascade of caspase activation, suggesting that the extrinsic pathway has a critical role in the apoptotic events induced by α-H. Furthermore, combined treatment of α-H with TRAIL enhanced apoptosis in HepG2 cells, activating caspase-8 and caspase-9. This correlated with up-regulation of both the TRAIL death receptor DR4 and DR5. DR4 or DR5 neutralizing antibodies abolished the effect of α-H on TRAIL-induced apoptosis, suggesting that sensitization was mediated through the death receptor pathway. Our results demonstrate that α-H induced apoptosis in the human hepatocellular carcinoma cell line HepG2 through activation of caspases and induction of the death receptor pathway. In addition, we describe a novel function of α-H as a sensitizer on TRAIL-induced apoptotic cell death in HepG2 cells. - Highlights: • α-Hispanolol induced apoptosis in the human hepatocellular carcinoma cell line HepG2. • α-Hispanolol induced activation of caspases and the death receptor pathway. • �

Programmed death receptor-1/programmed death receptor ligand-1 blockade after transient lymphodepletion to treat myeloma.

PubMed

Kearl, Tyce J; Jing, Weiqing; Gershan, Jill A; Johnson, Bryon D

2013-06-01

Early phase clinical trials targeting the programmed death receptor-1/ligand-1 (PD-1/PD-L1) pathway to overcome tumor-mediated immunosuppression have reported promising results for a variety of cancers. This pathway appears to play an important role in the failure of immune reactivity to malignant plasma cells in multiple myeloma patients, as the tumor cells express relatively high levels of PD-L1, and T cells show increased PD-1 expression. In the current study, we demonstrate that PD-1/PD-L1 blockade with a PD-L1-specific Ab elicits rejection of a murine myeloma when combined with lymphodepleting irradiation. This particular combined approach by itself has not previously been shown to be efficacious in other tumor models. The antitumor effect of lymphodepletion/anti-PD-L1 therapy was most robust when tumor Ag-experienced T cells were present either through cell transfer or survival after nonmyeloablative irradiation. In vivo depletion of CD4 or CD8 T cells completely eliminated antitumor efficacy of the lymphodepletion/anti-PD-L1 therapy, indicating that both T cell subsets are necessary for tumor rejection. Elimination of myeloma by T cells occurs relatively quickly as tumor cells in the bone marrow were nearly nondetectable by 5 d after the first anti-PD-L1 treatment, suggesting that antimyeloma reactivity is primarily mediated by preactivated T cells, rather than newly generated myeloma-reactive T cells. Anti-PD-L1 plus lymphodepletion failed to improve survival in two solid tumor models, but demonstrated significant efficacy in two hematologic malignancy models. In summary, our results support the clinical testing of lymphodepletion and PD-1/PD-L1 blockade as a novel approach for improving the survival of patients with multiple myeloma.

P2X Receptors as Drug Targets

PubMed Central

Jarvis, Michael F.

2013-01-01

The study of P2X receptors has long been handicapped by a poverty of small-molecule tools that serve as selective agonists and antagonists. There has been progress, particularly in the past 10 years, as cell-based high-throughput screening methods were applied, together with large chemical libraries. This has delivered some drug-like molecules in several chemical classes that selectively target P2X1, P2X3, or P2X7 receptors. Some of these are, or have been, in clinical trials for rheumatoid arthritis, pain, and cough. Current preclinical research programs are studying P2X receptor involvement in pain, inflammation, osteoporosis, multiple sclerosis, spinal cord injury, and bladder dysfunction. The determination of the atomic structure of P2X receptors in closed and open (ATP-bound) states by X-ray crystallography is now allowing new approaches by molecular modeling. This is supported by a large body of previous work using mutagenesis and functional expression, and is now being supplemented by molecular dynamic simulations and in silico ligand docking. These approaches should lead to P2X receptors soon taking their place alongside other ion channel proteins as therapeutically important drug targets. PMID:23253448

Absence of death receptor translocation into lipid rafts in acquired TRAIL-resistant NSCLC cells.

PubMed

Ouyang, Wen; Yang, Chunxu; Zhang, Simin; Liu, Yu; Yang, Bo; Zhang, Junhong; Zhou, Fuxiang; Zhou, Yunfeng; Xie, Conghua

2013-02-01

Resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a major limitation for its clinical use. The mechanisms of TRAIL resistance have been mostly studied in the context of cell lines that are intrinsically resistant to TRAIL. However, little is known about the molecular alterations that contribute to the development of acquired resistance during treatment with TRAIL. In this study, we established H460R, an isogenic cell line with acquired TRAIL resistance, from the TRAIL‑sensitive human lung cancer cell line H460 to investigate the mechanisms of acquired resistance. The acquired TRAIL‑resistant H460R cells remained sensitive to cisplatin. The mRNA and protein expression levels of death receptor 4 (DR4) and death receptor 5 (DR5) were not altered in either of the TRAIL-treated cell lines. Nevertheless, tests in which the DR4 or DR5 gene was overexpressed or silenced suggest that death receptor expression is necessary but not sufficient for TRAIL‑induced apoptosis. Compared with parental TRAIL-sensitive H460 cells, H460R cells showed a decreased TRAIL-induced translocation of DR4/DR5 into lipid rafts. Further studies showed that nystatin partially prevented lipid raft aggregation and DR4 and DR5 clustering and reduced apoptosis in H460 cells again. Analysis of apoptotic molecules showed that more pro-caspase-8, FADD, caspase-3 and Bid, but less cFLIP in H460 cells than in H460R cells. Our findings suggest that the lack of death receptor redistribution negatively impacts DISC assembly in lipid rafts, which at least partially leads to the development of acquired resistance to TRAIL in H460R cells.

Gene Expression Analysis Implicates a Death Receptor Pathway in Schizophrenia Pathology

PubMed Central

Catts, Vibeke Sørensen; Shannon Weickert, Cynthia

2012-01-01

An increase in apoptotic events may underlie neuropathology in schizophrenia. By data-mining approaches, we identified significant expression changes in death receptor signaling pathways in the dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia, particularly implicating the Tumor Necrosis Factor Superfamily member 6 (FAS) receptor and the Tumor Necrosis Factor [ligand] Superfamily member 13 (TNFSF13) in schizophrenia. We sought to confirm and replicate in an independent tissue collection the noted mRNA changes with quantitative real-time RT-PCR. To test for regional and diagnostic specificity, tissue from orbital frontal cortex (OFC) was examined and a bipolar disorder group included. In schizophrenia, we confirmed and replicated significantly increased expression of TNFSF13 mRNA in the DLPFC. Also, a significantly larger proportion of subjects in the schizophrenia group had elevated FAS receptor expression in the DLPFC relative to unaffected controls. These changes were not observed in the bipolar disorder group. In the OFC, there were no significant differences in TNFSF13 or FAS receptor mRNA expression. Decreases in BH3 interacting domain death agonist (BID) mRNA transcript levels were found in the schizophrenia and bipolar disorder groups affecting both the DLPFC and the OFC. We tested if TNFSF13 mRNA expression correlated with neuronal mRNAs in the DLPFC, and found significant negative correlations with interneuron markers, parvalbumin and somatostatin, and a positive correlation with PPP1R9B (spinophilin), but not DLG4 (PSD-95). The expression of TNFSF13 mRNA in DLPFC correlated negatively with tissue pH, but decreasing pH in cultured cells did not cause increased TNFSF13 mRNA nor did exogenous TNFSF13 decrease pH. We concluded that increased TNFSF13 expression may be one of several cell-death cytokine abnormalities that contribute to the observed brain pathology in schizophrenia, and while increased TNFSF13 may be associated with lower

Prostanoid receptor EP2 as a therapeutic target.

PubMed

Ganesh, Thota

2014-06-12

Cycoloxygenase-2 (COX-2) induction is prevalent in a variety of (brain and peripheral) injury models where COX-2 levels correlate with disease progression. Thus, COX-2 has been widely explored for anti-inflammatory therapy with COX-2 inhibitors, which proved to be effective in reducing the pain and inflammation in patients with arthritis and menstrual cramps, but they have not provided any benefit to patients with chronic inflammatory neurodegenerative disease. Recently, two COX-2 drugs, rofecoxib and valdecoxib, were withdrawn from the United States market due to cardiovascular side effects. Thus, future anti-inflammatory therapy could be targeted through a specific prostanoid receptor downstream of COX-2. The PGE2 receptor EP2 is emerging as a pro-inflammatory target in a variety of CNS and peripheral diseases. Here we highlight the latest developments on the role of EP2 in diseases, mechanism of activation, and small molecule discovery targeted either to enhance or to block the function of this receptor.

Cocaine Disrupts Histamine H3 Receptor Modulation of Dopamine D1 Receptor Signaling: σ1-D1-H3 Receptor Complexes as Key Targets for Reducing Cocaine's Effects

PubMed Central

Moreno, Estefanía; Moreno-Delgado, David; Navarro, Gemma; Hoffmann, Hanne M.; Fuentes, Silvia; Rosell-Vilar, Santi; Gasperini, Paola; Rodríguez-Ruiz, Mar; Medrano, Mireia; Mallol, Josefa; Cortés, Antoni; Casadó, Vicent; Lluís, Carme; Ferré, Sergi; Ortiz, Jordi; Canela, Enric

2014-01-01

The general effects of cocaine are not well understood at the molecular level. What is known is that the dopamine D1 receptor plays an important role. Here we show that a key mechanism may be cocaine's blockade of the histamine H3 receptor-mediated inhibition of D1 receptor function. This blockade requires the σ1 receptor and occurs upon cocaine binding to σ1-D1-H3 receptor complexes. The cocaine-mediated disruption leaves an uninhibited D1 receptor that activates Gs, freely recruits β-arrestin, increases p-ERK 1/2 levels, and induces cell death when over activated. Using in vitro assays with transfected cells and in ex vivo experiments using both rats acutely treated or self-administered with cocaine along with mice depleted of σ1 receptor, we show that blockade of σ1 receptor by an antagonist restores the protective H3 receptor-mediated brake on D1 receptor signaling and prevents the cell death from elevated D1 receptor signaling. These findings suggest that a combination therapy of σ1R antagonists with H3 receptor agonists could serve to reduce some effects of cocaine. PMID:24599455

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor

PubMed Central

Mavlyutov, Timur A.; Nickells, Robert W.

2011-01-01

Purpose The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1−/−) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Methods Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1−/− mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Results Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1−/−, demonstrating a significant difference between the wild-type and the Sigmar1−/− in crush-induced ganglion cell loss. Conclusions Our data indicated faster retinal ganglion cell death in Sigmar1−/− than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma. PMID

Farnesoid-X Receptor (FXR) as a Promising Pharmaceutical Target in Atherosclerosis.

PubMed

Moris, Demetrios; Giaginis, Constantinos; Tsourouflis, Gerasimos; Theocharis, Stamatios

2017-05-31

Atherosclerosis (AS) is a major cause of death and morbidity in Western world and is strongly connected with atherogenic lipoproteins and inflammation. Bile acids (BA) act as activating signals of endogenous ligands such as Farnesoid-X receptor (FXR). Primary data indicate a potential role of FXR in AS. The therapeutic value of FXR ligands in AS is unknown. With the present review, we analyzed the efficacy of FXR agonists as a therapeutic modalities against AS. In this aspect, we performed an electronic search through Pub- Med/MEDLINE database by using the key terms: FXR*, Farnesoid X receptor*, atherosclerosis*, bile acids* and agonism*. According to our analysis, the FXR seems to be a promising therapeutic target in the atherosclerosis natural history. FXR agonism could exert protective effects in the development and evolution of AS. However, concomitant side effects such as the reduction of plasma HDL have been reported. Finally, results from undergoing clinical trials with synthetic FXR agonists will shed more light to the precise role of FXR agonism in AS treatment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

PubMed

Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

2017-07-17

Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

Extracting ligands from receptors by reversed targeted molecular dynamics.

PubMed

Wolf, Romain M

2015-11-01

Short targeted MD trajectories are used to expel ligands from binding sites. The expulsion is governed by a linear increase of the target RMSD value, growing from zero to an arbitrary chosen final RMSD that forces the ligand to a selected distance outside of the receptor. The RMSD lag (i.e., the difference between the imposed and the actual RMSD) can be used to follow barriers encountered by the ligand during its way out of the receptor. The force constant used for the targeted MD can transform the RMSD lag into a strain energy. Integration of the (time-dependent) strain energy over time yields a value with the dimensions of "action" (i.e, energy multiplied by time) and can serve as a measure for the overall effort required to extract the ligand from its binding site. Possibilities to compare (numerically and graphically) the randomly detected exit pathways are discussed. As an example, the method is tested on the exit of bisphenol A from the human estrogen-related receptor [Formula: see text] and of GW0072 from the peroxysome proliferator activated receptor.

Influence of Berry-Polyphenols on Receptor Signaling and Cell-Death Pathways: Implications for Breast Cancer Prevention

PubMed Central

Aiyer, Harini S; Warri, Anni M; Woode, Denzel R; Hilakivi-Clarke, Leena; Clarke, Robert

2012-01-01

Breast cancer is the most commonly diagnosed cancer among women worldwide. Many women have become more aware of the benefits of increasing fruit consumption, as part of a healthy lifestyle, for the prevention of cancer. The mechanisms by which fruits, including berries, prevent breast cancer can be partially explained by exploring their interactions with pathways known influence cell-proliferation and evasion of cell-death. Two receptor pathways- estrogen receptor (ER) and tyrosine kinase receptors, especially the epidermal growth factor receptor (EGFR) family- are drivers of cell-proliferation and play a significant role in the development of both primary and recurrent breast cancer. There is strong evidence to show that several phytochemicals present in berries such as cyanidin, delphinidin, quercetin, kaempferol, ellagic acid, resveratrol and pterostilbene, interact with and alter the effects of these pathways. Further, they also induce cell death (apoptosis and autophagy) via their influence on kinase signaling. In this review, we summarize in vitro data regarding the interaction of berry polyphenols with the specific receptors and the mechanisms by which they induce cell death. Further, we also present in vivo data of primary breast cancer prevention by individual compounds and whole berries. Finally, we present a possible role for berries and berry compounds in the prevention of breast cancer and our perspective on the areas that require further research. PMID:22300613

Functional autoantibodies targeting G protein-coupled receptors in rheumatic diseases.

PubMed

Cabral-Marques, Otavio; Riemekasten, Gabriela

2017-11-01

G protein-coupled receptors (GPCRs) comprise the largest and most diverse family of integral membrane proteins that participate in different physiological processes such as the regulation of the nervous and immune systems. Besides the endogenous ligands of GPCRs, functional autoantibodies are also able to bind GPCRs to trigger or block intracellular signalling pathways, resulting in agonistic or antagonistic effects, respectively. In this Review, the effects of functional GPCR-targeting autoantibodies on the pathogenesis of autoimmune diseases, including rheumatic diseases, are discussed. Autoantibodies targeting β1 and β2 adrenergic receptors, which are expressed by cardiac and airway smooth muscle cells, respectively, have an important role in the development of asthma and cardiovascular diseases. In addition, high levels of autoantibodies against the muscarinic acetylcholine receptor M3 as well as those targeting endothelin receptor type A and type 1 angiotensin II receptor have several implications in the pathogenesis of rheumatic diseases such as Sjögren syndrome and systemic sclerosis. Expanding the knowledge of the pathophysiological roles of autoantibodies against GPCRs will shed light on the biology of these receptors and open avenues for new therapeutic approaches.

Tumor-targeting domains for chimeric antigen receptor T cells.

PubMed

Bezverbnaya, Ksenia; Mathews, Ashish; Sidhu, Jesse; Helsen, Christopher W; Bramson, Jonathan L

2017-01-01

Immunotherapy with chimeric antigen receptor (CAR) T cells has been advancing steadily in clinical trials. Since the ability of engineered T cells to recognize intended tumor-associated targets is crucial for the therapeutic success, antigen-binding domains play an important role in shaping T-cell responses. Single-chain antibody and T-cell receptor fragments, natural ligands, repeat proteins, combinations of the above and universal tag-specific domains have all been used in the antigen-binding moiety of chimeric receptors. Here we outline the advantages and disadvantages of different domains, discuss the concepts of affinity and specificity, and highlight the recent progress of each targeting strategy.

TRAIL Death Receptor-4, Decoy Receptor-1 and Decoy Receptor-2 Expression on CD8+ T Cells Correlate with the Disease Severity in Patients with Rheumatoid Arthritis

PubMed Central

2010-01-01

Background Rheumatoid Arthritis (RA) is a chronic autoimmune inflammatory disorder. Although the pathogenesis of disease is unclear, it is well known that T cells play a major role in both development and perpetuation of RA through activating macrophages and B cells. Since the lack of TNF-Related Apoptosis Inducing Ligand (TRAIL) expression resulted in defective thymocyte apoptosis leading to an autoimmune disease, we explored evidence for alterations in TRAIL/TRAIL receptor expression on peripheral T lymphocytes in the molecular mechanism of RA development. Methods The expression of TRAIL/TRAIL receptors on T cells in 20 RA patients and 12 control individuals were analyzed using flow cytometry. The correlation of TRAIL and its receptor expression profile was compared with clinical RA parameters (RA activity scored as per DAS28) using Spearman Rho Analysis. Results While no change was detected in the ratio of CD4+ to CD8+ T cells between controls and RA patient groups, upregulation of TRAIL and its receptors (both death and decoy) was detected on both CD4+ and CD8+ T cells in RA patients compared to control individuals. Death Receptor-4 (DR4) and the decoy receptors DcR1 and DcR2 on CD8+ T cells, but not on CD4+ T cells, were positively correlated with patients' DAS scores. Conclusions Our data suggest that TRAIL/TRAIL receptor expression profiles on T cells might be important in revelation of RA pathogenesis. PMID:20799941

Cannabinoid Receptor Type 1 Agonist ACEA Protects Neurons from Death and Attenuates Endoplasmic Reticulum Stress-Related Apoptotic Pathway Signaling.

PubMed

Vrechi, Talita A; Crunfli, Fernanda; Costa, Andressa P; Torrão, Andréa S

2018-05-01

Neurodegeneration is the result of progressive destruction of neurons in the central nervous system, with unknown causes and pathological mechanisms not yet fully elucidated. Several factors contribute to neurodegenerative processes, including neuroinflammation, accumulation of neurotoxic factors, and misfolded proteins in the lumen of the endoplasmic reticulum (ER). Endocannabinoid signaling has been pointed out as an important modulatory system in several neurodegeneration-related processes, inhibiting the inflammatory response and increasing neuronal survival. Thus, we investigated the presumptive protective effect of the selective cannabinoid type 1 (CB1) receptor agonist arachidonyl-2'-chloroethylamide (ACEA) against inflammatory (lipopolysaccharide, LPS) and ER stress (tunicamycin) stimuli in an in vitro neuronal model (Neuro-2a neuroblastoma cells). Cell viability analysis revealed that ACEA was able to protect against cell death induced by LPS and tunicamycin. This neuroprotective effect occurs via the CB1 receptor in the inflammation process and via the transient receptor potential of vanilloid type-1 (TRPV1) channel in ER stress. Furthermore, the immunoblotting analyses indicated that the neuroprotective effect of ACEA seems to involve the modulation of eukaryotic initiation factor 2 (eIF2α), transcription factor C/EBP homologous protein (CHOP), and caspase 12, as well as the survival/death p44/42 MAPK, ERK1/2-related signaling pathways. Together, these data suggest that the endocannabinoid system is a potential therapeutic target in neurodegenerative processes, especially in ER-related neurodegenerative diseases.

Death receptor-independent FADD signalling triggers hepatitis and hepatocellular carcinoma in mice with liver parenchymal cell-specific NEMO knockout.

PubMed

Ehlken, H; Krishna-Subramanian, S; Ochoa-Callejero, L; Kondylis, V; Nadi, N E; Straub, B K; Schirmacher, P; Walczak, H; Kollias, G; Pasparakis, M

2014-11-01

Hepatocellular carcinoma (HCC) usually develops in the context of chronic hepatitis triggered by viruses or toxic substances causing hepatocyte death, inflammation and compensatory proliferation of liver cells. Death receptors of the TNFR superfamily regulate cell death and inflammation and are implicated in liver disease and cancer. Liver parenchymal cell-specific ablation of NEMO/IKKγ, a subunit of the IκB kinase (IKK) complex that is essential for the activation of canonical NF-κB signalling, sensitized hepatocytes to apoptosis and caused the spontaneous development of chronic hepatitis and HCC in mice. Here we show that hepatitis and HCC development in NEMO(LPC-KO) mice is triggered by death receptor-independent FADD-mediated hepatocyte apoptosis. TNF deficiency in all cells or conditional LPC-specific ablation of TNFR1, Fas or TRAIL-R did not prevent hepatocyte apoptosis, hepatitis and HCC development in NEMO(LPC-KO) mice. To address potential functional redundancies between death receptors we generated and analysed NEMO(LPC-KO) mice with combined LPC-specific deficiency of TNFR1, Fas and TRAIL-R and found that also simultaneous lack of all three death receptors did not prevent hepatocyte apoptosis, chronic hepatitis and HCC development. However, LPC-specific combined deficiency in TNFR1, Fas and TRAIL-R protected the NEMO-deficient liver from LPS-induced liver failure, showing that different mechanisms trigger spontaneous and LPS-induced hepatocyte apoptosis in NEMO(LPC-KO) mice. In addition, NK cell depletion did not prevent liver damage and hepatitis. Moreover, NEMO(LPC-KO) mice crossed into a RAG-1-deficient genetic background-developed hepatitis and HCC. Collectively, these results show that the spontaneous development of hepatocyte apoptosis, chronic hepatitis and HCC in NEMO(LPC-KO) mice occurs independently of death receptor signalling, NK cells and B and T lymphocytes, arguing against an immunological trigger as the critical stimulus driving

S-SAD phasing study of death receptor 6 and its solution conformation revealed by SAXS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ru, Heng; Graduate University of Chinese Academy of Sciences, Beijing 100 049; Zhao, Lixia

A comparative analysis of sulfur phasing of death receptor 6 (DR6) using data collected at wavelengths of 2.0 and 2.7 Å is presented. SAXS analysis of unliganded DR6 defines a dimer as the minimum physical unit in solution. A subset of tumour necrosis factor receptor (TNFR) superfamily members contain death domains in their cytoplasmic tails. Death receptor 6 (DR6) is one such member and can trigger apoptosis upon the binding of a ligand by its cysteine-rich domains (CRDs). The crystal structure of the ectodomain (amino acids 1–348) of human death receptor 6 (DR6) encompassing the CRD region was phased usingmore » the anomalous signal from S atoms. In order to explore the feasibility of S-SAD phasing at longer wavelengths (beyond 2.5 Å), a comparative study was performed on data collected at wavelengths of 2.0 and 2.7 Å. In spite of sub-optimal experimental conditions, the 2.7 Å wavelength used for data collection showed potential for S-SAD phasing. The results showed that the R{sub ano}/R{sub p.i.m.} ratio is a good indicator for monitoring the anomalous data quality when the anomalous signal is relatively strong, while d′′/sig(d′′) calculated by SHELXC is a more sensitive and stable indicator applicable for grading a wider range of anomalous data qualities. The use of the ‘parameter-space screening method’ for S-SAD phasing resulted in solutions for data sets that failed during manual attempts. SAXS measurements on the ectodomain suggested that a dimer defines the minimal physical unit of an unliganded DR6 molecule in solution.« less

The Sigma Receptor Ligand (+)-Pentazocine Prevents Apoptotic Retinal Ganglion Cell Death induced in vitro by Homocysteine and Glutamate

PubMed Central

Martin, Pamela Moore; Ola, Mohammad S.; Agarwal, Neeraj; Ganapathy, Vadivel; Smith, Sylvia B.

2013-01-01

Recent studies demonstrated that the excitotoxic amino acid homocysteine induces apoptotic death of retinal ganglion cells in vivo. In the present study, an in vitro rat retinal ganglion cell (RGC-5) culture system was used to analyze the toxicity of acute exposure to high levels of homocysteine, the mechanism of homocysteine-induced toxicity and the usefulness of σR1 ligands as neuroprotectants. When cultured RGC-5 cells were subjected to treatment with 1 mM D, L- homocysteine, a significant increase in cell death was detected by TUNEL analysis and analysis of activated caspase. When cells were treated with homocysteine- or glutamate in the presence of MK-801, an antagonist of the NMDA receptor, the cell death was inhibited significantly. In contrast, NBQX, an antagonist of the AMPA/Kainate receptor, and nifedipine, a calcium channel blocker, did not prevent the homocysteine- or glutamate-induced cell death. Semi-quantitative RT-PCR and immunocytochemical analysis demonstrated that RGC-5 cells exposed to homocysteine or glutamate express type 1 sigma receptor at levels similar to control cells. Treatment of RGC-5 cells with 3 µM or 10 µM concentrations of the σR1-specific ligand (+)-pentazocine inhibited significantly the apoptotic cell death induced by homocysteine or glutamate. The results suggest that homocysteine is toxic to ganglion cells in vitro, that the toxicity is mediated via NMDA receptor activation, and that the σR1-specific ligand (+)-pentazocine can block the RGC-5 cell death induced by homocysteine and glutamate. PMID:15046867

Therapeutic antibody targeting of individual Notch receptors.

PubMed

Wu, Yan; Cain-Hom, Carol; Choy, Lisa; Hagenbeek, Thijs J; de Leon, Gladys P; Chen, Yongmei; Finkle, David; Venook, Rayna; Wu, Xiumin; Ridgway, John; Schahin-Reed, Dorreyah; Dow, Graham J; Shelton, Amy; Stawicki, Scott; Watts, Ryan J; Zhang, Jeff; Choy, Robert; Howard, Peter; Kadyk, Lisa; Yan, Minhong; Zha, Jiping; Callahan, Christopher A; Hymowitz, Sarah G; Siebel, Christian W

2010-04-15

The four receptors of the Notch family are widely expressed transmembrane proteins that function as key conduits through which mammalian cells communicate to regulate cell fate and growth. Ligand binding triggers a conformational change in the receptor negative regulatory region (NRR) that enables ADAM protease cleavage at a juxtamembrane site that otherwise lies buried within the quiescent NRR. Subsequent intramembrane proteolysis catalysed by the gamma-secretase complex liberates the intracellular domain (ICD) to initiate the downstream Notch transcriptional program. Aberrant signalling through each receptor has been linked to numerous diseases, particularly cancer, making the Notch pathway a compelling target for new drugs. Although gamma-secretase inhibitors (GSIs) have progressed into the clinic, GSIs fail to distinguish individual Notch receptors, inhibit other signalling pathways and cause intestinal toxicity, attributed to dual inhibition of Notch1 and 2 (ref. 11). To elucidate the discrete functions of Notch1 and Notch2 and develop clinically relevant inhibitors that reduce intestinal toxicity, we used phage display technology to generate highly specialized antibodies that specifically antagonize each receptor paralogue and yet cross-react with the human and mouse sequences, enabling the discrimination of Notch1 versus Notch2 function in human patients and rodent models. Our co-crystal structure shows that the inhibitory mechanism relies on stabilizing NRR quiescence. Selective blocking of Notch1 inhibits tumour growth in pre-clinical models through two mechanisms: inhibition of cancer cell growth and deregulation of angiogenesis. Whereas inhibition of Notch1 plus Notch2 causes severe intestinal toxicity, inhibition of either receptor alone reduces or avoids this effect, demonstrating a clear advantage over pan-Notch inhibitors. Our studies emphasize the value of paralogue-specific antagonists in dissecting the contributions of distinct Notch receptors to

Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma

PubMed Central

Hubbard, Molly; Nordmann, Tyler; Sperduto, Paul W; Clark, H. Brent; Hunt, Matthew A

2017-01-01

Learning objectives To evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists. Introduction  Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution. Methods Records from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented.  Results A total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies. Conclusions This data suggests that there is need for

Anticancer molecules targeting fibroblast growth factor receptors.

PubMed

Liang, Guang; Liu, Zhiguo; Wu, Jianzhang; Cai, Yuepiao; Li, Xiaokun

2012-10-01

The fibroblast growth factor receptor (FGFR) family includes four highly conserved receptor tyrosine kinases: FGFR1-4. Upon ligand binding, FGFRs activate an array of downstream signaling pathways, such as the mitogen activated protein kinase (MAPK) and the phosphoinositide-3-kinase (PI3K)/Akt pathways. These FGFR cascades play crucial roles in tumor cell proliferation, angiogenesis, migration, and survival. The combination of knockdown studies and pharmaceutical inhibition in preclinical models demonstrates that FGFRs are attractive targets for therapeutic intervention in cancer. Multiple FGFR inhibitors with various structural skeletons have been designed, synthesized, and evaluated. Reviews on FGFRs have recently focused on FGFR signaling, pathophysiology, and functions in cancer or other diseases. In this article, we review recent advances in structure-activity relationships (SAR) of FGFR inhibitors, as well as the FGFR-targeting drug design strategies currently employed in targeting deregulated FGFRs by antibodies and small molecule inhibitors. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biological Functionalization of Drug Delivery Carriers to Bypass Size Restrictions of Receptor-Mediated Endocytosis Independently from Receptor Targeting

PubMed Central

Ansar, Maria; Serrano, Daniel; Papademetriou, Iason; Bhowmick, Tridib Kumar; Muro, Silvia

2014-01-01

Targeting of drug carriers to cell-surface receptors involved in endocytosis is commonly used for intracellular drug delivery. However, most endocytic receptors mediate uptake via clathrin or caveolar pathways associated with ≤200-nm vesicles, restricting carrier design. We recently showed that endocytosis mediated by intercellular adhesion molecule 1 (ICAM-1), which differs from clathrin- and caveolar-mediated pathways, allows uptake of nano- and micro-carriers in cell culture and in vivo due to recruitment of cellular sphingomyelinases to the plasmalemma. This leads to ceramide generation at carrier binding sites and formation of actin stress-fibers, enabling engulfment and uptake of a wide size-range of carriers. Here we adapted this paradigm to enhance uptake of drug carriers targeted to receptors associated with size-restricted pathways. We coated sphingomyelinase onto model (polystyrene) submicro- and micro-carriers targeted to clathrin-associated mannose-6-phosphate receptor. In endothelial cells, this provided ceramide enrichment at the cell surface and actin stress-fiber formation, modifying the uptake pathway and enhancing carrier endocytosis without affecting targeting, endosomal transport, cell-associated degradation, or cell viability. This improvement depended on the carrier size and enzyme dose, and similar results were observed for other receptors (transferrin receptor) and cell types (epithelial cells). This phenomenon also enhanced tissue accumulation of carriers after intravenous injection in mice. Hence, it is possible to maintain targeting toward a selected receptor while bypassing natural size-restrictions of its associated endocytic route by functionalization of drug carriers with biological elements mimicking the ICAM-1 pathway. This strategy holds considerable promise to enhance flexibility of design of targeted drug delivery systems. PMID:24237309

Biological functionalization of drug delivery carriers to bypass size restrictions of receptor-mediated endocytosis independently from receptor targeting.

PubMed

Ansar, Maria; Serrano, Daniel; Papademetriou, Iason; Bhowmick, Tridib Kumar; Muro, Silvia

2013-12-23

Targeting of drug carriers to cell-surface receptors involved in endocytosis is commonly used for intracellular drug delivery. However, most endocytic receptors mediate uptake via clathrin or caveolar pathways associated with ≤200-nm vesicles, restricting carrier design. We recently showed that endocytosis mediated by intercellular adhesion molecule 1 (ICAM-1), which differs from clathrin- and caveolae-mediated pathways, allows uptake of nano- and microcarriers in cell culture and in vivo due to recruitment of cellular sphingomyelinases to the plasmalemma. This leads to ceramide generation at carrier binding sites and formation of actin stress-fibers, enabling engulfment and uptake of a wide size-range of carriers. Here we adapted this paradigm to enhance uptake of drug carriers targeted to receptors associated with size-restricted pathways. We coated sphingomyelinase onto model (polystyrene) submicro- and microcarriers targeted to clathrin-associated mannose-6-phosphate receptor. In endothelial cells, this provided ceramide enrichment at the cell surface and actin stress-fiber formation, modifying the uptake pathway and enhancing carrier endocytosis without affecting targeting, endosomal transport, cell-associated degradation, or cell viability. This improvement depended on the carrier size and enzyme dose, and similar results were observed for other receptors (transferrin receptor) and cell types (epithelial cells). This phenomenon also enhanced tissue accumulation of carriers after intravenous injection in mice. Hence, it is possible to maintain targeting toward a selected receptor while bypassing natural size restrictions of its associated endocytic route by functionalization of drug carriers with biological elements mimicking the ICAM-1 pathway. This strategy holds considerable promise to enhance flexibility of design of targeted drug delivery systems.

Sigma-2 ligands and PARP inhibitors synergistically trigger cell death in breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Elizabeth S.; Mankoff, Julia; Makvandi, Mehran

The sigma-2 receptor is overexpressed in proliferating cells compared to quiescent cells and has been used as a target for imaging solid tumors by positron emission tomography. Recent work has suggested that the sigma-2 receptor may also be an effective therapeutic target for cancer therapy. Poly (ADP-ribose) polymerase (PARP) is a family of enzymes involved in DNA damage response. In this study, we looked for potential synergy of cytotoxicity between PARP inhibitors and sigma-2 receptor ligands in breast cancer cell lines. We showed that the PARP inhibitor, YUN3-6, sensitized mouse breast cancer cell line, EMT6, to sigma-2 receptor ligand (SV119,more » WC-26, and RHM-138) induced cell death determined by cell viability assay and colony forming assay. The PARP inhibitor, olaparib, sensitized tumor cells to a different sigma-2 receptor ligand SW43-induced apoptosis and cell death in human triple negative cell line, MDA-MB-231. Olaparib inhibited PARP activity and cell proliferation, and arrested cells in G2/M phase of the cell cycle in MDA-MB-231 cells. Subsequently cells became sensitized to SW43 induced cell death. In conclusion, the combination of sigma-2 receptor ligands and PARP inhibitors appears to hold promise for synergistically triggering cell death in certain types of breast cancer cells and merits further investigation. - Highlights: • PARPi, YUN3-6 and olaparib, and σ2 ligands, SV119 and SW43, were evaluated. • Mouse and human breast cancer cells, EMT6 and MDA-MB-231 respectively, were used. • YUN3-6 and SV119 synergistically triggered cell death in EMT6 cells. • Olaparib and SW43 additively triggered cell death in MDA-MB-231 cells. • Olaparib arrested cells in G2/M in MDA-MB-231 cells.« less

TRAF2 multitasking in TNF receptor-induced signaling to NF-κB, MAP kinases and cell death.

PubMed

Borghi, Alice; Verstrepen, Lynn; Beyaert, Rudi

2016-09-15

Tumor Necrosis Factor (TNF) is a potent inflammatory cytokine that exerts its functions through the activation of two distinct receptors, TNFR1 and TNFR2. Both receptors can activate canonical NF-κB and JNK MAP kinase signaling, while TNFR2 can also activate non-canonical NF-κB signaling, leading to numerous changes in gene expression that drive inflammation, cell proliferation and cell survival. On the other hand, TNFR1 also activates signaling pathways leading to cell death by either apoptosis or necroptosis, depending on the cellular context. A key player in TNFR1- and TNFR2-induced signaling is the RING finger protein TRAF2, which is recruited to both receptors upon their stimulation. TRAF2 exerts multiple receptor-specific functions but also mediates cross-talk between TNFR1 and TNFR2, dictating the outcome of TNF stimulation. In this review, we provide an overview of the positive and negative regulatory role of TRAF2 in different TNFR1 and TNFR2 signaling pathways. We discuss the underlying molecular mechanism of action, distinguishing between TRAF2 scaffold and E3 ubiquitin ligase functions, and the regulation of TRAF2 by specific post-translational modifications. Finally, we elaborate on some possible strategies to modulate TRAF2 function in the context of therapeutic targeting in autoimmunity and cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Death Receptor 6 Promotes Wallerian Degeneration in Peripheral Axons.

PubMed

Gamage, Kanchana K; Cheng, Irene; Park, Rachel E; Karim, Mardeen S; Edamura, Kazusa; Hughes, Christopher; Spano, Anthony J; Erisir, Alev; Deppmann, Christopher D

2017-03-20

Axon degeneration during development is required to sculpt a functional nervous system and is also a hallmark of pathological insult, such as injury [1, 2]. Despite similar morphological characteristics, very little overlap in molecular mechanisms has been reported between pathological and developmental degeneration [3-5]. In the peripheral nervous system (PNS), developmental axon pruning relies on receptor-mediated extrinsic degeneration mechanisms to determine which axons are maintained or degenerated [5-7]. Receptors have not been implicated in Wallerian axon degeneration; instead, axon autonomous, intrinsic mechanisms are thought to be the primary driver for this type of axon disintegration [8-10]. Here we survey the role of neuronally expressed, paralogous tumor necrosis factor receptor super family (TNFRSF) members in Wallerian degeneration. We find that an orphan receptor, death receptor 6 (DR6), is required to drive axon degeneration after axotomy in sympathetic and sensory neurons cultured in microfluidic devices. We sought to validate these in vitro findings in vivo using a transected sciatic nerve model. Consistent with the in vitro findings, DR6 -/- animals displayed preserved axons up to 4 weeks after injury. In contrast to phenotypes observed in Wld s and Sarm1 -/- mice, preserved axons in DR6 -/- animals display profound myelin remodeling. This indicates that deterioration of axons and myelin after axotomy are mechanistically distinct processes. Finally, we find that JNK signaling after injury requires DR6, suggesting a link between this novel extrinsic pathway and the axon autonomous, intrinsic pathways that have become established for Wallerian degeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure-based receptor MIMICS targeted against bacterial superantigen toxins

DOEpatents

Gupta, Goutam [Santa Fe, NM; Hong-Geller, Elizabeth [Los Alamos, NM; Shiflett, Patrick R [Los Alamos, NM; Lehnert, Nancy M [Albuquerque, NM

2009-08-18

The invention provides therapeutic compositions useful in the treatment of bacterial superantigen mediated conditions, such as Toxic Shock Syndrome. The compositions comprise genetically engineered bifunctional polypeptides containing a specific T-cell receptor binding domain and a specific MHC class II receptor binding domain, each targeting non-overlapping epitopes on a superantigen molecule against which they are designed. The anti-superantigen "receptor mimetics" or "chimeras" are rationally designed to recreate the modality of superantigen binding directly to both the TCR and the MHC-II receptor, and are capable of acting as decoys for superantigen binding, effectively out-competing the host T-cell and MHC-II receptors, the natural host receptors.

Lorcaserin and pimavanserin: emerging selectivity of serotonin receptor subtype–targeted drugs

PubMed Central

Meltzer, Herbert Y.; Roth, Bryan L.

2013-01-01

Serotonin (5-hydroxytryptamine, or 5-HT) receptors mediate a plethora of physiological phenomena in the brain and the periphery. Additionally, serotonergic dysfunction has been implicated in nearly every neuropsychiatric disorder. The effects of serotonin are mediated by fourteen GPCRs. Both the therapeutic actions and side effects of commonly prescribed drugs are frequently due to nonspecific actions on various 5-HT receptor subtypes. For more than 20 years, the search for clinically efficacious drugs that selectively target 5-HT receptor subtypes has been only occasionally successful. This review provides an overview of 5-HT receptor pharmacology and discusses two recent 5-HT receptor subtype–selective drugs, lorcaserin and pimavanserin, which target the 5HT2C and 5HT2A receptors and provide new treatments for obesity and Parkinson’s disease psychosis, respectively. PMID:24292660

Lorcaserin and pimavanserin: emerging selectivity of serotonin receptor subtype-targeted drugs.

PubMed

Meltzer, Herbert Y; Roth, Bryan L

2013-12-01

Serotonin (5-hydroxytryptamine, or 5-HT) receptors mediate a plethora of physiological phenomena in the brain and the periphery. Additionally, serotonergic dysfunction has been implicated in nearly every neuropsychiatric disorder. The effects of serotonin are mediated by fourteen GPCRs. Both the therapeutic actions and side effects of commonly prescribed drugs are frequently due to nonspecific actions on various 5-HT receptor subtypes. For more than 20 years, the search for clinically efficacious drugs that selectively target 5-HT receptor subtypes has been only occasionally successful. This review provides an overview of 5-HT receptor pharmacology and discusses two recent 5-HT receptor subtype-selective drugs, lorcaserin and pimavanserin, which target the 5HT2C and 5HT2A receptors and provide new treatments for obesity and Parkinson's disease psychosis, respectively.

Targeting Programmed Cell Death Using Small-Molecule Compounds to Improve Potential Cancer Therapy.

PubMed

Ke, Bowen; Tian, Mao; Li, Jingjing; Liu, Bo; He, Gu

2016-11-01

Evasion of cell death is one of the hallmarks of cancer cells, beginning with long-established apoptosis and extending to other new forms of cell death. An elaboration of cell death pathways thus will contribute to a better understanding of cancer pathogenesis and therapeutics. With the recent substantial biochemical and genetic explorations of cell death subroutines, their classification has switched from primarily morphological to more molecular definitions. According to their measurable biochemical features and intricate mechanisms, cell death subroutines can be divided into apoptosis, autophagic cell death, mitotic catastrophe, necroptosis, parthanatos, ferroptosis, pyroptosis, pyronecrosis, anoikis, cornification, entosis, and NETosis. Supportive evidence has gradually revealed the prime molecular mechanisms of each subroutine and thus providing series of possible targets in cancer therapy, while the intricate relationships between different cell death subroutines still remain to be clarified. Over the past decades, cancer drug discovery has significantly benefited from the use of small-molecule compounds to target classical modalities of cell death such as apoptosis, while newly identified cell death subroutines has also emerging their potential for cancer drug discovery in recent years. In this review, we comprehensively focus on summarizing 12 cell death subroutines and discussing their corresponding small-molecule compounds in potential cancer therapy. Together, these inspiring findings may provide more evidence to fill in the gaps between cell death subroutines and small-molecule compounds to better develop novel cancer therapeutic strategies. © 2016 Wiley Periodicals, Inc.

Orphan Nuclear Receptors as Targets for Drug Development

PubMed Central

Mukherjee, Subhajit

2012-01-01

Orphan nuclear receptors regulate diverse biological processes. These important molecules are ligand-activated transcription factors that act as natural sensors for a wide range of steroid hormones and xenobiotic ligands. Because of their importance in regulating various novel signaling pathways, recent research has focused on identifying xenobiotics targeting these receptors for the treatment of multiple human diseases. In this review, we will highlight these receptors in several physiologic and pathophysiologic actions and demonstrate how their functions can be exploited for the successful development of newer drugs. PMID:20372994

Natriuretic peptide receptor A inhibition suppresses gastric cancer development through reactive oxygen species-mediated G2/M cell cycle arrest and cell death.

PubMed

Li, Zheng; Wang, Ji-Wei; Wang, Wei-Zhi; Zhi, Xiao-Fei; Zhang, Qun; Li, Bo-Wen; Wang, Lin-Jun; Xie, Kun-Ling; Tao, Jin-Qiu; Tang, Jie; Wei, Song; Zhu, Yi; Xu, Hao; Zhang, Dian-Cai; Yang, Li; Xu, Ze-Kuan

2016-10-01

Natriuretic peptide receptor A (NPRA), the major receptor for atrial natriuretic peptide (ANP), has been implicated in tumorigenesis; however, the role of ANP-NPRA signaling in the development of gastric cancer remains unclear. Immunohistochemical analyses indicated that NPRA expression was positively associated with gastric tumor size and cancer stage. NPRA inhibition by shRNA induced G2/M cell cycle arrest, cell death, and autophagy in gastric cancer cells, due to accumulation of reactive oxygen species (ROS). Either genetic or pharmacologic inhibition of autophagy led to caspase-dependent cell death. Therefore, autophagy induced by NPRA silencing may represent a cytoprotective mechanism. ROS accumulation activated c-Jun N-terminal kinase (JNK) and AMP-activated protein kinase (AMPK). ROS-mediated activation of JNK inhibited cell proliferation by disturbing cell cycle and decreased cell viability. In addition, AMPK activation promoted autophagy in NPRA-downregulated cancer cells. Overall, our results indicate that the inhibition of NPRA suppresses gastric cancer development and targeting NPRA may represent a promising strategy for the treatment of gastric cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Targeting the folate receptor: improving efficacy in inorganic medicinal chemistry.

PubMed

Carron, Pauraic Mc; Crowley, Aisling; O'Shea, Denis; McCann, Malachy; Howe, Orla; Hunt, Mary; Devereux, Michael

2018-02-09

The discovery of the high-affinity, high-specificity folate receptor in mamalian kidney cells, coupled with the ability of folate to enter cells by folate receptor-mediated endocytosis and the subsequent elucidation of the folate receptor's overexpression in specific cancer cell types; heralded the arrival of the area of chemotherapeutic folate targeting. The application of purely organic folate-based small-molecule drug conjugates that selectively target the folate receptor, which is over expressed in several diseases such as cancer, is well established. The application of inorganic folate-targeted drugs offers significant potential to expand and enhance this therapeutic approach. From the data made available to date, it is apparent that this aspect of inorganic medicinal chemistry is in its youth but has the capability to contribute greatly to cancer research, both in therapy and diagnosis. The union of folate-receptor targeting and inorganic medicine may also lead to the development of treatments for disorders such as chronic-inflammation, tuberculosis, neurodegenerative disease and leishmaniasis. In this review, we summarize what is known about the coordination chemistry of folic acid and the therapeutic potential of such complexes. We also describe approaches adopted to conjugate platinum drugs to folate- or folate-carrier- systems and their prospective ability to overcome problems associated with unwanted side-effects and resistance by improving their delivery and/or selectivity. The literature pertaining to non-platinum metal complex conjugates with folic acid is also reviewed revealing that this is an area that offers significant potential to develop targeted therapeutic approaches in areas such as chemotherapy and molecular imaging for diagnostics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Virus-encoded chemokine receptors--putative novel antiviral drug targets.

PubMed

Rosenkilde, Mette M

2005-01-01

Large DNA viruses, in particular herpes- and poxviruses, have evolved proteins that serve as mimics or decoys for endogenous proteins in the host. The chemokines and their receptors serve key functions in both innate and adaptive immunity through control of leukocyte trafficking, and have as such a paramount role in the antiviral immune responses. It is therefore not surprising that viruses have found ways to exploit and subvert the chemokine system by means of molecular mimicry. By ancient acts of molecular piracy and by induction and suppression of endogenous genes, viruses have utilized chemokines and their receptors to serve a variety of roles in viral life-cycle. This review focuses on the pharmacology of virus-encoded chemokine receptors, yet also the family of virus-encoded chemokines and chemokine-binding proteins will be touched upon. Key properties of the virus-encoded receptors, compared to their closest endogenous homologs, are interactions with a wider range of chemokines, which can act as agonists, antagonists and inverse agonists, and the exploitation of many signal transduction pathways. High constitutive activity is another key property of some--but not all--of these receptors. The chemokine receptors belong to the superfamily of G-protein coupled 7TM receptors that per se are excellent drug targets. At present, non-peptide antagonists have been developed against many chemokine receptors. The potentials of the virus-encoded chemokine receptors as drug targets--ie. as novel antiviral strategies--will be highlighted here together with the potentials of the virus-encoded chemokines and chemokine-binding proteins as novel anti-inflammatory biopharmaceutical strategies.

Meconium increases type 1 angiotensin II receptor expression and alveolar cell death.

PubMed

Rosenfeld, Charles R; Zagariya, Alexander M; Liu, Xiao-Tie; Willis, Brigham C; Fluharty, Steven; Vidyasagar, Dharmapuri

2008-03-01

The pulmonary renin-angiotensin system (RAS) contributes to inflammation and epithelial apoptosis in meconium aspiration. It is unclear if both angiotensin II receptors (ATR) contribute, where they are expressed and if meconium modifies subtype expression. We examined ATR subtypes in 2 wk rabbit pup lungs before and after meconium exposure and with and without captopril pretreatment or type 1 receptor (AT1R) inhibition with losartan, determining expression and cellular localization with immunoblots, RT-PCR and immunohistochemistry, respectively. Responses of cultured rat alveolar type II pneumocytes were also examined. Type 2 ATR were undetected in newborn lung before and after meconium instillation. AT1R were expressed in pulmonary vascular and bronchial smooth muscle and alveolar and bronchial epithelium. Meconium increased total lung AT1R protein approximately 3-fold (p = 0.006), mRNA 29% (p = 0.006) and immunostaining in bronchial and alveolar epithelium and smooth muscle, which were unaffected by captopril and losartan. Meconium also increased AT1R expression >3-fold in cultured type II pneumocytes and caused concentration-dependent cell death inhibited by losartan. Meconium increases AT1R expression in newborn rabbit lung and cultured type II pneumocytes and induces AT1R-mediated cell death. The pulmonary RAS contributes to the pathogenesis of meconium aspiration through increased receptor expression.

Harnessing tumor necrosis factor receptors to enhance antitumor activities of drugs.

PubMed

Muntané, Jordi

2011-10-17

Cancer is the second-leading cause of death in the U.S. behind heart disease and over stroke. The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The inhibition of cell death pathways is one of these tumor characteristics which also include sustained proliferative signaling, evading growth suppressor signaling, replicative immortality, angiogenesis, and promotion of invasion and metastasis. Cell death is mediated through death receptor (DR) stimulation initiated by specific ligands that transmit signaling to the cell death machinery or through the participation of mitochondria. Cell death involving DR is mediated by the superfamily of tumor necrosis factor receptor (TNF-R) which includes TNF-R type I, CD95, DR3, TNF-related apoptosis-inducing ligand (TRAIL) receptor-1 (TRAIL-R1) and -2 (TRAIL-R2), DR6, ectodysplasin A (EDA) receptor (EDAR), and the nerve growth factor (NGF) receptor (NGFR). The expression of these receptors in healthy and tumor cells induces treatment side effects that limit the systemic administration of cell death-inducing therapies. The present review is focused on the different therapeutic strategies such as targeted antibodies or small molecules addressed to selective stimulated DR-mediated apoptosis or reduce cell proliferation in cancer cells.

Novel approaches for targeting the adenosine A2A receptor.

PubMed

Yuan, Gengyang; Gedeon, Nicholas G; Jankins, Tanner C; Jones, Graham B

2015-01-01

The adenosine A2A receptor (A2AR) represents a drug target for a wide spectrum of diseases. Approaches for targeting this membrane-bound protein have been greatly advanced by new stabilization techniques. The resulting X-ray crystal structures and subsequent analyses provide deep insight to the A2AR from both static and dynamic perspectives. Application of this, along with other biophysical methods combined with fragment-based drug design (FBDD), has become a standard approach in targeting A2AR. Complementarities of in silico screening based- and biophysical screening assisted- FBDD are likely to feature in future approaches in identifying novel ligands against this key receptor. This review describes evolution of the above approaches for targeting A2AR and highlights key modulators identified. It includes a review of: adenosine receptor structures, homology modeling, X-ray structural analysis, rational drug design, biophysical methods, FBDD and in silico screening. As a drug target, the A2AR is attractive as its function plays a role in a wide spectrum of diseases including oncologic, inflammatory, Parkinson's and cardiovascular diseases. Although traditional approaches such as high-throughput screening and homology model-based virtual screening (VS) have played a role in targeting A2AR, numerous shortcomings have generally restricted their applications to specific ligand families. Using stabilization methods for crystallization, X-ray structures of A2AR have greatly accelerated drug discovery and influenced development of biophysical-in silico hybrid screening methods. Application of these new methods to other ARs and G-protein-coupled receptors is anticipated in the future.

Differential immunomodulatory activity of tumor cell death induced by cancer therapeutic toll-like receptor ligands.

PubMed

Klein, Johanna C; Wild, Clarissa A; Lang, Stephan; Brandau, Sven

2016-06-01

Synthetic toll-like receptor (TLR) ligands stimulate defined immune cell subsets and are currently tested as novel immunotherapeutic agents against cancer with, however, varying clinical efficacy. Recent data showed the expression of TLR receptors also on tumor cells. In this study we investigated immunological events associated with the induction of tumor cell death by poly(I:C) and imiquimod. A human head and neck squamous cell carcinoma (HNSCC) cell line was exposed to poly(I:C) and imiquimod, which were delivered exogenously via culture medium or via electroporation. Cell death and cell biological consequences thereof were analyzed. For in vivo analyses, a human xenograft and a syngeneic immunocompetent mouse model were used. Poly(I:C) induced cell death only if delivered by electroporation into the cytosol. Cell death induced by poly(I:C) resulted in cytokine release and activation of monocytes in vitro. Monocytes activated by the supernatant of cancer cells previously exposed to poly(I:C) recruited significantly more Th1 cells than monocytes exposed to control supernatants. If delivered exogenously, imiquimod also induced tumor cell death and some release of interleukin-6, but cell death was not associated with release of Th1 cytokines, interferons, monocyte activation and Th1 recruitment. Interestingly, intratumoral injection of poly(I:C) triggered tumor cell death in tumor-bearing mice and reduced tumor growth independent of TLR signaling on host cells. Imiquimod did not affect tumor size. Our data suggest that common cancer therapeutic RNA compounds can induce functionally diverse types of cell death in tumor cells with implications for the use of TLR ligands in cancer immunotherapy.

Secreted calmodulin-like skin protein inhibits neuronal death in cell-based Alzheimer's disease models via the heterotrimeric Humanin receptor

PubMed Central

Hashimoto, Y; Nawa, M; Kurita, M; Tokizawa, M; Iwamatsu, A; Matsuoka, M

2013-01-01

Humanin is a secreted bioactive peptide that is protective in a variety of death models, including cell-based neuronal death models related to Alzheimer's disease (AD). To mediate the protective effect in AD-related death models, Humanin signals via a cell-surface receptor that is generally composed of three subunits: ciliary neurotrophic factor receptor α, WSX-1 and gp130 (heterotrimeric Humanin receptor; htHNR). However, the protective effect of Humanin via the htHNR is weak (EC50=1–10 μℳ); therefore, it is possible that another physiological agonist for this receptor exists in vivo. In the current study, calmodulin-like skin protein (CLSP), a calmodulin relative with an undefined function, was shown to be secreted and inhibit neuronal death via the htHNR with an EC50 of 10–100 pℳ. CLSP was highly expressed in the skin, and the concentration in circulating normal human blood was ∼5 nℳ. When administered intraperitoneally in mice, recombinant CLSP was transported across the blood-cerebrospinal fluid (CSF)-barrier and its concentration in the CSF reaches 1/100 of its serum concentration at 1 h after injection. These findings suggest that CLSP is a physiological htHNR agonist. PMID:23519124

Novel receptor-targeted contrast agents for optical imaging of tumors

NASA Astrophysics Data System (ADS)

Becker, Andreas; Hessenius, Carsten; Bhargava, Sarah; Ebert, Bernd; Sukowski, Uwe; Rinneberg, Herbert H.; Wiedenmann, Bertram; Semmler, Wolfhard; Licha, Kai

2000-04-01

Many gastroenteropancreatic tumors express receptors for somatostatin (SST) and/or vasoactive intestinal peptide (VIP). These receptors can be used as molecular targets for the delivery of contrast agents for tumor diagnostics. We have synthesized conjugates consisting of a cyanine dye and an SST analogue or VIP for use as contrast agents in optical imaging. Receptor binding and internalization of these compounds were examined with optical methods in transfected RIN38 tumor cells expressing the SST2 receptor or a GFP- labeled VIP (VPAC1) receptor. Furthermore, biodistribution of the conjugates was examined by laser-induced fluorescence imaging in nude mice bearing SST2 or VPAC1 receptor- expressing tumors. After incubation of RIN38 SSTR2 cells in the presence of 100 nM indotricarbocyanine-SST analogue, cell-associated fluorescence increased, whereas no increase was observed when receptor-medicated endocytosis was inhibited. Indodicarbocyanine-VIP accumulated in RIN38 VPAC1 cells and co-localization with the GFP-labeled VPAC1 receptor was observed. After injection of indotricarbocyanine-SST analogue into tumor-bearing nude mice, SST2 receptor-positive tumors could be visualized for a time period from 10 min to at least 48 h. After application of indodicarbocyanine-VIP, a fluorescence signal in VIP1 receptor-expressing tumors was only detected during the first hour. We conclude that cyanine dye-labeled VIP and SST analogue are novel, targeted contrast agents for the optical imaging of tumors expressing the relevant receptor.

Targeting nuclear receptors for the treatment of fatty liver disease.

PubMed

Tanaka, Naoki; Aoyama, Toshifumi; Kimura, Shioko; Gonzalez, Frank J

2017-11-01

Ligand-activated nuclear receptors, including peroxisome proliferator-activated receptor alpha (PPARα), pregnane X receptor, and constitutive androstane receptor, were first identified as key regulators of the responses against chemical toxicants. However, numerous studies using mouse disease models and human samples have revealed critical roles for these receptors and others, such as PPARβ/δ, PPARγ, farnesoid X receptor (FXR), and liver X receptor (LXR), in maintaining nutrient/energy homeostasis in part through modulation of the gut-liver-adipose axis. Recently, disorders associated with disrupted nutrient/energy homeostasis, e.g., obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD), are increasing worldwide. Notably, in NAFLD, a progressive subtype exists, designated as non-alcoholic steatohepatitis (NASH) that is characterized by typical histological features resembling alcoholic steatohepatitis (ASH), and NASH/ASH are recognized as major causes of hepatitis virus-unrelated liver cirrhosis and hepatocellular carcinoma. Since hepatic steatosis is basically caused by an imbalance between fat/energy influx and utilization, abnormal signaling of these nuclear receptors contribute to the pathogenesis of fatty liver disease. Standard therapeutic interventions have not been fully established for fatty liver disease, but some new agents that activate or inhibit nuclear receptor signaling have shown promise as possible therapeutic targets. In this review, we summarize recent findings on the roles of nuclear receptors in fatty liver disease and discuss future perspectives to develop promising pharmacological strategies targeting nuclear receptors for NAFLD/NASH. Copyright © 2017 Elsevier Inc. All rights reserved.

[Programmed necrosis mediated by receptor-interacting protein 3: a new target for liver disease research].

PubMed

Zhang, J; Jing, Y; Li, Y N; Zhou, L; Wang, B M

2016-09-20

Hepatocyte death mainly includes apoptosis and necrosis and is a critical process in the pathophysiological mechanism of liver injury caused by various reasons. Recent studies have shown that key regulatory molecules in the inhibition of apoptosis such as caspase cannot be used as targets for inhibiting disease progression in clinical practice. In recent years, programmed necrosis mediated by receptor-interacting protein 3(RIP3)becomes a new hot research topic. It not only plays an important role in inducing inflammatory response, but also is closely regulated by intracellular signal factors, and it is a type of active cell death which can be interfered with. Compared with apoptosis, programmed necrosis is accompanied by the release of various inflammatory factors, which significantly affects local immune microenvironment. RIP3-mediated programmed necrosis has been taken seriously in many diseases. Although its mechanism of action in liver disease remains unclear, the results of recent studies confirmed its important role in the development of liver disease. This article reviews the research advances in the role of RIP3-mediated programmed necrosis signaling pathway in liver disease of various causes and investigates the possibility of RIP3-mediated programmed necrosis as a new target in the treatment of liver disease.

Apoptosis gene expression and death receptor signaling in mitomycin-C-treated human tenon capsule fibroblasts.

PubMed

Crowston, Jonathan G; Chang, Lydia H; Constable, Peter H; Daniels, Julie T; Akbar, Arne N; Khaw, Peng T

2002-03-01

To examine the effect of mitomycin-C on the expression of apoptosis genes in human Tenon capsule fibroblasts and to evaluate whether death receptor signaling modulates mitomycin-C cytotoxicity. Bcl-2, Bax, Bcl-x, Fas (CD95) and tumor necrosis factor (TNF) receptor expression was determined by flow cytometry in control and mitomycin-C-treated Tenon fibroblasts. Fibroblast death was quantified using a lactate dehydrogenase release assay. The effect of Fas and TNF-receptor signaling was evaluated using Fas-specific antibodies and soluble TNF-alpha. Tenon fibroblasts constitutively express Bcl-2, Bax, and Bcl-x in culture. Mitomycin-C (0.4 mg/mL) induced a small but consistent increase in the expression of all three proteins. Tenon fibroblasts express low levels of Fas but are resistant to the effects of Fas-receptor ligation. Mitomycin-C (0.01-1.0 mg/mL) led to a significant increase in Fas expression at all concentrations tested (P < 0.01). Pretreatment with mitomycin-C (0.4 mg/mL) rendered fibroblasts susceptible to agonistic anti-Fas monoclonal IgM antibodies (50-500 ng/mL) and led to a further 50% reduction in viable fibroblasts at 48 hours, compared with mitomycin-C alone (P < 0.05). Antibodies that block the Fas receptor did not inhibit mitomycin-C-induced apoptosis. Mitomycin-C alters apoptosis gene expression and primes fibroblasts to the effects of Fas receptor ligation. Factors other than the level of Fas receptor expression modulate the response to Fas receptor signaling. Determining the signals that regulate fibroblast apoptosis may help to refine therapeutic strategies for switching off the subconjunctival healing response and maintaining intraocular pressure control.

Neuroprotective effect against axonal damage-induced retinal ganglion cell death in apolipoprotein E-deficient mice through the suppression of kainate receptor signaling.

PubMed

Omodaka, Kazuko; Nishiguchi, Koji M; Yasuda, Masayuki; Tanaka, Yuji; Sato, Kota; Nakamura, Orie; Maruyama, Kazuichi; Nakazawa, Toru

2014-10-24

Apolipoprotein E (ApoE) plays important roles in the body, including a carrier of cholesterols, an anti-oxidant, and a ligand for the low-density lipoprotein receptors. In the nervous system, the presence of ApoE4 isoforms is associated with Alzheimer's disease. ApoE gene polymorphisms are also associated with glaucoma, but the function of ApoE in the retina remains unclear. In this study, we investigated the role of ApoE in axonal damage-induced RGC death. ApoE was detected in the astrocytes and Müller cells in the wild-type (WT) retina. RGC damage was induced in adult ApoE-deficient mice (male, 10-12 weeks old) through ocular hypertension (OH), optic nerve crush (NC), or by administering kainic acid (KA) intravitreally. The WT mice were treated with a glutamate receptor antagonist (MK801 or CNQX) 30 min before performing NC or left untreated. Seven days later, the retinas were flat mounted and Fluorogold-labeled RGCs were counted. We found that the RGCs in the ApoE-deficient mice were resistant to OH-induced RGC death and optic nerve degeneration 4 weeks after induction. In WT mice, NC effectively induced RGC death (control: 4085±331 cells/mm(2), NC: 1728±170 cells/mm(2)). CNQX, an inhibitor of KA receptors, suppressed this RGC death (3031±246 cells/mm(2)), but MK801, an inhibitor of NMDA receptors, did not (1769±212 cells/mm(2)). This indicated the involvement of KA receptor signaling in NC-induced RGC death. We found that NC- or KA-induced RGC death was significantly less in the ApoE-deficient mice than in the WT mice. These data suggest that the ApoE deficiency had a neuroprotective effect against axonal damage-induced RGC death by suppressing the KA receptor signaling. Copyright © 2014 Elsevier B.V. All rights reserved.

Drug of the year: programmed death-1 receptor/programmed death-1 ligand-1 receptor monoclonal antibodies.

PubMed

Robert, Caroline; Soria, Jean-Charles; Eggermont, Alexander M M

2013-09-01

Programmed death-1 receptor (PD-1)/its ligand (PD-L1) antibodies have changed the landscape in oncology in 2013. The most mature results have been obtained in advanced melanoma patients. They indicate important response rates and high quality responses or prolonged duration. Also in renal cancer and in lung cancer remarkable activity has been demonstrated. Thus it is clear that these antibodies have a very broad potential and trials in many tumour types are being initiated. Breaking tolerance at the tumour site is a potent phenomenon and the potential for synergy with other checkpoint inhibitors such as ipilimumab have also been demonstrated in 2013. Long term tumour control now seems achievable and thus the concept of a clinical cure is emerging by modulation of the immune system. These antibodies bring immunotherapy to the forefront and indicate that immune-modulation will be a key component of therapeutic strategies from now on. Because of all these reasons PD-1/PD-L1 antibodies are considered 'drug of the year'. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transient Receptor Potential Vanilloid 1 Expression Mediates Capsaicin-Induced Cell Death.

PubMed

Ramírez-Barrantes, Ricardo; Córdova, Claudio; Gatica, Sebastian; Rodriguez, Belén; Lozano, Carlo; Marchant, Ivanny; Echeverria, Cesar; Simon, Felipe; Olivero, Pablo

2018-01-01

The transient receptor potential (TRP) ion channel family consists of a broad variety of non-selective cation channels that integrate environmental physicochemical signals for dynamic homeostatic control. Involved in a variety of cellular physiological processes, TRP channels are fundamental to the control of the cell life cycle. TRP channels from the vanilloid (TRPV) family have been directly implicated in cell death. TRPV1 is activated by pain-inducing stimuli, including inflammatory endovanilloids and pungent exovanilloids, such as capsaicin (CAP). TRPV1 activation by high doses of CAP (>10 μM) leads to necrosis, but also exhibits apoptotic characteristics. However, CAP dose-response studies are lacking in order to determine whether CAP-induced cell death occurs preferentially via necrosis or apoptosis. In addition, it is not known whether cytosolic Ca 2+ and mitochondrial dysfunction participates in CAP-induced TRPV1-mediated cell death. By using TRPV1-transfected HeLa cells, we investigated the underlying mechanisms involved in CAP-induced TRPV1-mediated cell death, the dependence of CAP dose, and the participation of mitochondrial dysfunction and cytosolic Ca 2+ increase. Together, our results contribute to elucidate the pathophysiological steps that follow after TRPV1 stimulation with CAP. Low concentrations of CAP (1 μM) induce cell death by a mechanism involving a TRPV1-mediated rapid and transient intracellular Ca 2+ increase that stimulates plasma membrane depolarization, thereby compromising plasma membrane integrity and ultimately leading to cell death. Meanwhile, higher doses of CAP induce cell death via a TRPV1-independent mechanism, involving a slow and persistent intracellular Ca 2+ increase that induces mitochondrial dysfunction, plasma membrane depolarization, plasma membrane loss of integrity, and ultimately, cell death.

Sudden death in the presence of overt beta-adrenergic receptor activation in guinea pigs immediately following isoflurane anesthesia.

PubMed

Overholser, Brian R; Zheng, Xiaomei; Pell, Carrie; Blickman, Andrew

2010-05-01

A case series of sudden death is reported in five consecutive guinea pigs following anesthesia with inhalational isoflurane during beta-adrenergic receptor stimulation with isoproterenol. Sustained-release isoproterenol pellets or mini-osmotic pumps were implanted subcutaneously in male Dunkin-Hartley guinea pigs as part of a research study to assess the interplay of adrenergic receptor activation and the development of atrial arrhythmias. The continuous exposure to isoproterenol resulted in a similar presentation and eventual sudden death in all guinea pigs exposed to inhalational isoflurane between 15 to 40 minutes after discontinuation of anesthesia. Death occurred in guinea pigs in this case series despite the fact that doses of isoproterenol used were more than 10-fold lower than previously reported in guinea pigs in the absence of isoflurane anesthesia. The cause of death was suspected to be due to an interaction of isoproterenol with isoflurane anesthesia, as placebo implantation or anesthesia alone did not result in cardiac arrest. Of four subsequent guinea pigs anesthetized with the combination of xylazine and ketamine (X/K), three survived isoproterenol implantation for the full 21-day study period while one died perioperatively. There was an increased rate of post-anesthetic mortality associated with isoproterenol pellet implantation in guinea pigs anesthetized with isoflurane compared to X/K. This may be due to the detrimental effects of the combination of isoflurane during overt beta-adrenergic receptor activation or cardioprotective effects of X/K anesthesia during beta-adrenergic receptor hyperactivity.

Co-targeting the HER and IGF/insulin receptor axis in breast cancer, with triple targeting with endocrine therapy for hormone-sensitive disease.

PubMed

Chakraborty, Ashok; Hatzis, Christos; DiGiovanna, Michael P

2017-05-01

Interactions between HER2, estrogen receptor (ER), and insulin-like growth factor I receptor (IGF1R) are implicated in resistance to monotherapies targeting these receptors. We have previously shown in pre-clinical studies synergistic anti-tumor effects for co-targeting each pairwise combination of HER2, IGF1R, and ER. Strikingly, synergy for HER2/IGF1R targeting occurred not only in a HER2+ model, but also in a HER2-normal model. The purpose of the current study was therefore to determine the generalizability of synergistic anti-tumor effects of co-targeting HER2/IGF1R, the anti-tumor activity of triple-targeting HER2/IGF1R/ER in hormone-dependent cell lines, and the effect of using the multi-targeting drugs neratinib (pan-HER) and BMS-754807 (dual IGF1R/insulin receptor). Proliferation and apoptosis assays were performed in a large panel of cell lines representing varying receptor expression levels. Mechanistic effects were studied using phospho-protein immunoblotting. Analyses of drug interaction effects were performed using linear mixed-effects regression models. Enhanced anti-proliferative effects of HER/IGF-insulin co-targeting were seen in most, though not all, cell lines, including HER2-normal lines. For ER+ lines, triple targeting with inclusion of anti-estrogen generally resulted in the greatest anti-tumor effects. Double or triple targeting generally resulted in marked increases in apoptosis in the sensitive lines. Mechanistic studies demonstrated that the synergy between drugs was correlated with maximal inhibition of Akt and ERK pathway signaling. Dual HER/IGF-insulin targeting, and triple targeting with inclusion of anti-estrogen drugs, shows striking anti-tumor activity across breast cancer types, and drugs with broader receptor specificity may be more effective than single receptor selective drugs, particularly for ER- cells.

Advances of Molecular Targeted Therapy in Gastric Cancer.

PubMed

Cetin, Bulent; Gumusay, Ozge; Cengiz, Mustafa; Ozet, Ahmet

2016-06-01

Gastric cancer is the second most common cause of cancer-related death in the world, and its prognosis remains poor with a median overall survival of 12 months for advanced disease. Advances in the understanding of molecular genetics have led to the development of directed molecular targeted therapy in gastric cancer, leading to improve patient outcomes and quality of life. In the treatment of human epidermal growth factor receptor 2 (HER2)-positive gastric cancer, the addition of trastuzumab significantly improves survival in the first-line setting of therapy. Ramucirumab, an antibody directed against vascular endothelial growth factor receptor 2, significantly improved progression-free and overall survival and has been approved for second-line treatment of gastric cancer. Anti-mesenchymal-epithelial transition (c-MET), mammalian target of rapamycin inhibitors, and polo-like kinase 1 inhibitors are under investigation as a novel therapeutic option for the treatment of gastric cancer. The novel therapies target the key immune checkpoint interaction between a T cell co-inhibitory receptor called programmed death 1 (PD-1) and one of its immunosuppressive ligands, PD-L1. This article reviews molecular targeted therapies in gastric cancer, in light of recent advances.

Rethinking Nuclear Receptors as Potential Therapeutic Targets for Retinal Diseases.

PubMed

Choudhary, Mayur; Malek, Goldis

2016-12-01

Collectively, retinal diseases, including age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy, result in severe vision impairment worldwide. The absence and/or limited availability of successful drug therapies for these blinding disorders necessitates further understanding their pathobiology and identifying new targetable signaling pathways. Nuclear receptors are transcription regulators of many key aspects of human physiology, as well as pathophysiology, with reported roles in development, aging, and disease. Some of the pathways regulated by nuclear receptors include, but are not limited to, angiogenesis, inflammation, and lipid metabolic dysregulation, mechanisms also important in the initiation and development of several retinal diseases. Herein, we present an overview of the biology of three diseases affecting the posterior eye, summarize a growing body of evidence that suggests direct or indirect involvement of nuclear receptors in disease progression, and discuss the therapeutic potential of targeting nuclear receptors for treatment.

Rethinking Nuclear Receptors as Potential Therapeutic Targets for Retinal Diseases

PubMed Central

Choudhary, Mayur; Malek, Goldis

2017-01-01

Collectively, retinal diseases, including age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy, result in severe vision impairment worldwide. The absence and/or limited availability of successful drug therapies for these blinding disorders necessitates further understanding their pathobiology and identifying new targetable signaling pathways. Nuclear receptors are transcription regulators of many key aspects of human physiology, as well as pathophysiology, with reported roles in development, aging, and disease. Some of the pathways regulated by nuclear receptors include, but are not limited to, angiogenesis, inflammation, and lipid metabolic dysregulation, mechanisms also important in the initiation and development of several retinal diseases. Herein, we present an overview of the biology of three diseases affecting the posterior eye, summarize a growing body of evidence that suggests direct or indirect involvement of nuclear receptors in disease progression, and discuss the therapeutic potential of targeting nuclear receptors for treatment. PMID:27455994

Endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 controls B-cell immunity through degradation of the death receptor CD95/Fas

PubMed Central

Kong, Sinyi; Yang, Yi; Xu, Yuanming; Wang, Yajun; Zhang, Yusi; Melo-Cardenas, Johanna; Xu, Xiangping; Gao, Beixue; Thorp, Edward B.; Zhang, Donna D.; Zhang, Bin; Song, Jianxun; Zhang, Kezhong; Zhang, Jianning; Zhang, Jinping; Li, Huabin; Fang, Deyu

2016-01-01

Humoral immunity involves multiple checkpoints during B-cell development, maturation, and activation. The cell death receptor CD95/Fas-mediated apoptosis plays a critical role in eliminating the unwanted activation of B cells by self-reactive antigens and in maintaining B-cell homeostasis through activation-induced B-cell death (AICD). The molecular mechanisms controlling AICD remain largely undefined. Herein, we show that the E3 ubiquitin ligase Hrd1 protected B cells from activation-induced cell death by degrading the death receptor Fas. Hrd1-null B cells exhibited high Fas expression during activation and rapidly underwent Fas-mediated apoptosis, which could be largely inhibited by FasL neutralization. Fas mutation in Hrd1 KO mice abrogated the increase in B-cell AICD. We identified Hrd1 as the first E3 ubiquitin ligase of the death receptor Fas and Hrd1-mediated Fas destruction as a molecular mechanism in regulating B-cell immunity. PMID:27573825

Endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 controls B-cell immunity through degradation of the death receptor CD95/Fas.

PubMed

Kong, Sinyi; Yang, Yi; Xu, Yuanming; Wang, Yajun; Zhang, Yusi; Melo-Cardenas, Johanna; Xu, Xiangping; Gao, Beixue; Thorp, Edward B; Zhang, Donna D; Zhang, Bin; Song, Jianxun; Zhang, Kezhong; Zhang, Jianning; Zhang, Jinping; Li, Huabin; Fang, Deyu

2016-09-13

Humoral immunity involves multiple checkpoints during B-cell development, maturation, and activation. The cell death receptor CD95/Fas-mediated apoptosis plays a critical role in eliminating the unwanted activation of B cells by self-reactive antigens and in maintaining B-cell homeostasis through activation-induced B-cell death (AICD). The molecular mechanisms controlling AICD remain largely undefined. Herein, we show that the E3 ubiquitin ligase Hrd1 protected B cells from activation-induced cell death by degrading the death receptor Fas. Hrd1-null B cells exhibited high Fas expression during activation and rapidly underwent Fas-mediated apoptosis, which could be largely inhibited by FasL neutralization. Fas mutation in Hrd1 KO mice abrogated the increase in B-cell AICD. We identified Hrd1 as the first E3 ubiquitin ligase of the death receptor Fas and Hrd1-mediated Fas destruction as a molecular mechanism in regulating B-cell immunity.

Cardiomyocytes undergo apoptosis in human immunodeficiency virus cardiomyopathy through mitochondrion- and death receptor-controlled pathways

PubMed Central

Twu, Cheryl; Liu, Nancy Q.; Popik, Waldemar; Bukrinsky, Michael; Sayre, James; Roberts, Jaclyn; Rania, Shammas; Bramhandam, Vishnu; Roos, Kenneth P.; MacLellan, W. Robb; Fiala, Milan

2002-01-01

We investigated 18 AIDS hearts (5 with and 13 without cardiomyopathy) by using immunocytochemistry and computerized image analysis regarding the roles of HIV-1 proteins and tumor necrosis factor ligands in HIV cardiomyopathy (HIVCM). HIVCM and cardiomyocyte apoptosis were significantly related to each other and to the expression by inflammatory cells of gp120 and tumor necrosis factor-α. In HIVCM heart, active caspase 9, a component of the mitochondrion-controlled apoptotic pathway, and the elements of the death receptor-mediated pathway, tumor necrosis factor-α and Fas ligand, were expressed strongly on macrophages and weakly on cardiomyocytes. HIVCM showed significantly greater macrophage infiltration and cardiomyocyte apoptosis rate compared with non-HIVCM. HIV-1 entered cultured neonatal rat ventricular myocytes by macropinocytosis but did not replicate. HIV-1- or gp120-induced apoptosis of rat myocytes through a mitochondrion-controlled pathway, which was inhibited by heparin, AOP-RANTES, or pertussis toxin, suggesting that cardiomyocyte apoptosis is induced by signaling through chemokine receptors. In conclusion, in patients with HIVCM, cardiomyocytes die through both mitochondrion- and death receptor-controlled apoptotic pathways. PMID:12379743

Cardiomyocytes undergo apoptosis in human immunodeficiency virus cardiomyopathy through mitochondrion- and death receptor-controlled pathways.

PubMed

Twu, Cheryl; Liu, Nancy Q; Popik, Waldemar; Bukrinsky, Michael; Sayre, James; Roberts, Jaclyn; Rania, Shammas; Bramhandam, Vishnu; Roos, Kenneth P; MacLellan, W Robb; Fiala, Milan

2002-10-29

We investigated 18 AIDS hearts (5 with and 13 without cardiomyopathy) by using immunocytochemistry and computerized image analysis regarding the roles of HIV-1 proteins and tumor necrosis factor ligands in HIV cardiomyopathy (HIVCM). HIVCM and cardiomyocyte apoptosis were significantly related to each other and to the expression by inflammatory cells of gp120 and tumor necrosis factor-alpha. In HIVCM heart, active caspase 9, a component of the mitochondrion-controlled apoptotic pathway, and the elements of the death receptor-mediated pathway, tumor necrosis factor-alpha and Fas ligand, were expressed strongly on macrophages and weakly on cardiomyocytes. HIVCM showed significantly greater macrophage infiltration and cardiomyocyte apoptosis rate compared with non-HIVCM. HIV-1 entered cultured neonatal rat ventricular myocytes by macropinocytosis but did not replicate. HIV-1- or gp120-induced apoptosis of rat myocytes through a mitochondrion-controlled pathway, which was inhibited by heparin, AOP-RANTES, or pertussis toxin, suggesting that cardiomyocyte apoptosis is induced by signaling through chemokine receptors. In conclusion, in patients with HIVCM, cardiomyocytes die through both mitochondrion- and death receptor-controlled apoptotic pathways.

Customizing the targeting of IGF-1 receptor.

PubMed

Baserga, Renato

2009-02-01

The type 1 IGF receptor (IGF-IR) is activated by two ligands, IGF-1 and IGF-2, and by insulin at supraphysiological concentrations. It plays a significant role in the growth of normal and abnormal cells, and antibodies against the IGF-IR are now in clinical trials. Targeting of the IGF-IR in cancer cells (by antibodies or other means) can be improved by the appropriate selection of responsive tumors. This review focuses on the optimization of IGF-IR targeting in human cancer.

Cannabinoid-induced cell death in endometrial cancer cells: involvement of TRPV1 receptors in apoptosis.

PubMed

Fonseca, B M; Correia-da-Silva, G; Teixeira, N A

2018-05-01

Among a variety of phytocannabinoids, Δ 9 -tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most promising therapeutic compounds. Besides the well-known palliative effects in cancer patients, cannabinoids have been shown to inhibit in vitro growth of tumor cells. Likewise, the major endocannabinoids (eCBs), anandamide (AEA) and 2-arachidonoylglycerol (2-AG), induce tumor cell death. The purpose of the present study was to characterize cannabinoid elements and evaluate the effect of cannabinoids in endometrial cancer cell viability. The presence of cannabinoid receptors, transient receptor potential vanilloid 1 (TRPV1), and endocannabinoid-metabolizing enzymes were determined by qRT-PCR and Western blot. We also examined the effects and the underlying mechanisms induced by eCBs and phytocannabinoids in endometrial cancer cell viability. Besides TRPV1, both EC cell lines express all the constituents of the endocannabinoid system. We observed that at concentrations higher than 5 μM, eCBs and CBD induced a significant reduction in cell viability in both Ishikawa and Hec50co cells, whereas THC did not cause any effect. In Ishikawa cells, contrary to Hec50co, treatment with AEA and CBD resulted in an increase in the levels of activated caspase -3/-7, in cleaved PARP, and in reactive oxygen species generation, confirming that the reduction in cell viability observed in the MTT assay was caused by the activation of the apoptotic pathway. Finally, these effects were dependent on TRPV1 activation and intracellular calcium levels. These data indicate that cannabinoids modulate endometrial cancer cell death. Selective targeting of TPRV1 by AEA, CBD, or other stable analogues may be an attractive research area for the treatment of estrogen-dependent endometrial carcinoma. Our data further support the evaluation of CBD and CBD-rich extracts for the potential treatment of endometrial cancer, particularly, that has become non-responsive to common therapies.

Death receptor 3 signaling enhances proliferation of human regulatory T cells.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Ehrenschwender, Martin

2017-04-01

Exploiting regulatory T cells (Tregs) to control aberrant immune reactions is a promising therapeutic approach, but is hampered by their relative paucity. In mice, activation of death receptor 3 (DR3), a member of the TNF-receptor superfamily (TNFRSF), increases Treg frequency and efficiently controls exuberant immune activation. For human Tregs, neither DR3 expression nor potential functions have been described. Here, we show that human Tregs express DR3 and demonstrate DR3-mediated activation of p38, ERK, and NFκB. DR3 stimulation enhances Treg expansion ex vivo while retaining their suppressive capacity. In summary, our results establish a functional role for DR3 signaling in human Tregs and could potentially help to tailor Treg-based therapies. © 2017 Federation of European Biochemical Societies.

Peptide receptor targeting in cancer: the somatostatin paradigm.

PubMed

Barbieri, Federica; Bajetto, Adriana; Pattarozzi, Alessandra; Gatti, Monica; Würth, Roberto; Thellung, Stefano; Corsaro, Alessandro; Villa, Valentina; Nizzari, Mario; Florio, Tullio

2013-01-01

Peptide receptors involved in pathophysiological processes represent promising therapeutic targets. Neuropeptide somatostatin (SST) is produced by specialized cells in a large number of human organs and tissues. SST primarily acts as inhibitor of endocrine and exocrine secretion via the activation of five G-protein-coupled receptors, named sst1-5, while in central nervous system, SST acts as a neurotransmitter/neuromodulator, regulating locomotory and cognitive functions. Critical points of SST/SST receptor biology, such as signaling pathways of individual receptor subtypes, homo- and heterodimerization, trafficking, and cross-talk with growth factor receptors, have been extensively studied, although functions associated with several pathological conditions, including cancer, are still not completely unraveled. Importantly, SST exerts antiproliferative and antiangiogenic effects on cancer cells in vitro, and on experimental tumors in vivo. Moreover, SST agonists are clinically effective as antitumor agents for pituitary adenomas and gastro-pancreatic neuroendocrine tumors. However, SST receptors being expressed by tumor cells of various tumor histotypes, their pharmacological use is potentially extendible to other cancer types, although to date no significant results have been obtained. In this paper the most recent findings on the expression and functional roles of SST and SST receptors in tumor cells are discussed.

Targeting receptor-mediated endocytotic pathways with nanoparticles: rationale and advances

PubMed Central

Xu, Shi; Olenyuk, Bogdan Z.; Okamoto, Curtis T.; Hamm-Alvarez, Sarah F.

2012-01-01

Targeting of drugs and their carrier systems by using receptor-mediated endocytotic pathways was in its nascent stages 25 years ago. In the intervening years, an explosion of knowledge focused on design and synthesis of nanoparticulate delivery systems as well as elucidation of the cellular complexity of what was previously-termed receptor-mediated endocytosis has now created a situation when it has become possible to design and test the feasibility of delivery of highly specific nanoparticle drug carriers to specific cells and tissue. This review outlines the mechanisms governing the major modes of receptor-mediated endocytosis used in drug delivery and highlights recent approaches using these as targets for in vivo drug delivery of nanoparticles. The review also discusses some of the inherent complexity associated with the simple shift from a ligand-drug conjugate versus a ligand-nanoparticle conjugate, in terms of ligand valency and its relationship to the mode of receptor-mediated internalization. PMID:23026636

Repurposing anticancer drugs for targeting necroptosis.

PubMed

Fulda, Simone

2018-04-25

Necroptosis represents a form of programmed cell death that can be engaged by various upstream signals, for example by ligation of death receptors, by viral sensors or by pattern recognition receptors. It depends on several key signaling proteins, including the kinases Receptor-Interacting Protein (RIP)1 and RIP3 and the pseudokinase mixed-lineage kinase domain-like protein (MLKL). Necroptosis has been implicated in a number of physiological and pathophysiological conditions and is disturbed in many human diseases. Thus, targeted interference with necroptosis signaling may offer new opportunities for the treatment of human diseases. Besides structure-based drug design, in recent years drug repositioning has emerged as a promising alternative to develop drug-like compounds. There is accumulating evidence showing that multi-targeting kinase inhibitors, for example Dabrafenib, Vemurafenib, Sorafenib, Pazopanib and Ponatinib, used for the treatment of cancer also display anti-necroptotic activity. This review summarizes recent evidence indicating that some anticancer kinase inhibitors also negatively affect necroptosis signaling. This implies that some cancer therapeutics may be repurposed for other pathologies, e.g. ischemic or inflammatory diseases.

Drug delivery to the human and mouse uterus using immunoliposomes targeted to the oxytocin receptor.

PubMed

Paul, Jonathan W; Hua, Susan; Ilicic, Marina; Tolosa, Jorge M; Butler, Trent; Robertson, Sarah; Smith, Roger

2017-03-01

The ability to provide safe and effective pharmacotherapy during obstetric complications, such as preterm labor or postpartum hemorrhage, is hampered by the systemic toxicity of therapeutic agents leading to adverse side effects in the mother and fetus. Development of novel strategies to target tocolytic and uterotonic agents specifically to uterine myocytes would improve therapeutic efficacy while minimizing the risk of side effects. Ligand-targeted liposomes have emerged as a reliable and versatile platform for targeted drug delivery to specific cell types, tissues or organs. Our objective was to develop a targeted drug delivery system for the uterus utilizing an immunoliposome platform targeting the oxytocin receptor. We conjugated liposomes to an antibody that recognizes an extracellular domain of the oxytocin receptor. We then examined the ability of oxytocin receptor-targeted liposomes to deliver contraction-blocking (nifedipine, salbutamol and rolipram) or contraction-enhancing (dofetilide) agents to strips of spontaneously contracting myometrial tissue in vitro (human and mouse). We evaluated the ability of oxytocin receptor-targeted liposomes to localize to uterine tissue in vivo, and assessed if targeted liposomes loaded with indomethacin were capable of preventing lipopolysaccharide-induced preterm birth in mice. Oxytocin receptor-targeted liposomes loaded with nifedipine, salbutamol or rolipram consistently abolished human myometrial contractions in vitro, while oxytocin receptor-targeted liposomes loaded with dofetilide increased contraction duration. Nontargeted control liposomes loaded with these agents had no effect. Similar results were observed in mouse uterine strips. Following in vivo administration to pregnant mice, oxytocin receptor-targeted liposomes localized specifically to the uterine horns and mammary tissue. Targeting increased localization to the uterus 7-fold. Localization was not detected in the maternal brain or fetus. Targeted

Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer

DTIC Science & Technology

2010-05-01

TITLE: Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer PRINCIPAL INVESTIGATOR...May 2009 - 30 Apr 2010 4. TITLE AND SUBTITLE Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer...telomerase as a potential target of AR signaling suppression by selenium . We found that combination of selenium and bicalutamide produced a robust down

Principles of antibody-mediated TNF receptor activation

PubMed Central

Wajant, H

2015-01-01

From the beginning of research on receptors of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF), agonistic antibodies have been used to stimulate TNFRSF receptors in vitro and in vivo. Indeed, CD95, one of the first cloned TNFRSF receptors, was solely identified as the target of cell death-inducing antibodies. Early on, it became evident from in vitro studies that valency and Fcγ receptor (FcγR) binding of antibodies targeting TNFRSF receptors can be of crucial relevance for agonistic activity. TNFRSF receptor-specific antibodies of the IgM subclass and secondary cross-linked or aggregation prone dimeric antibodies typically display superior agonistic activity compared with dimeric antibodies. Likewise, anchoring of antibodies to cell surface-expressed FcγRs potentiate their ability to trigger TNFRSF receptor signaling. However, only recently has the relevance of oligomerization and FcγR binding for the in vivo activity of antibody-induced TNFRSF receptor activation been straightforwardly demonstrated in vivo. This review discusses the crucial role of oligomerization and/or FcγR binding for antibody-mediated TNFRSF receptor stimulation in light of current models of TNFRSF receptor activation and especially the overwhelming relevance of these issues for the rational development of therapeutic TNFRSF receptor-targeting antibodies. PMID:26292758

Glutamate and Its Receptors as Therapeutic Targets for Migraine.

PubMed

Hoffmann, Jan; Charles, Andrew

2018-04-01

There is substantial evidence indicating a role for glutamate in migraine. Levels of glutamate are higher in the brain and possibly also in the peripheral circulation in migraine patients, particularly during attacks. Altered blood levels of kynurenines, endogenous modulators of glutamate receptors, have been reported in migraine patients. Population genetic studies implicate genes that are involved with glutamate signaling in migraine, and gene mutations responsible for familial hemiplegic migraine and other familial migraine syndromes may influence glutamate signaling. Animal studies indicate that glutamate plays a key role in pain transmission, central sensitization, and cortical spreading depression. Multiple therapies that target glutamate receptors including magnesium, topiramate, memantine, and ketamine have been reported to have efficacy in the treatment of migraine, although with the exception of topiramate, the evidence for the efficacy of these therapies is not strong. Also, because all of these therapies have other mechanisms of action, it is not possible to conclude that the efficacy of these drugs is entirely due to their effects on glutamate receptors. Further studies are needed to more clearly delineate the possible roles of glutamate and its specific receptor subtypes in migraine and to identify new ways of targeting glutamate for migraine therapy.

TRAIL-death receptor endocytosis and apoptosis are selectively regulated by dynamin-1 activation.

PubMed

Reis, Carlos R; Chen, Ping-Hung; Bendris, Nawal; Schmid, Sandra L

2017-01-17

Clathrin-mediated endocytosis (CME) constitutes the major pathway for uptake of signaling receptors into eukaryotic cells. As such, CME regulates signaling from cell-surface receptors, but whether and how specific signaling receptors reciprocally regulate the CME machinery remains an open question. Although best studied for its role in membrane fission, the GTPase dynamin also regulates early stages of CME. We recently reported that dynamin-1 (Dyn1), previously assumed to be neuron-specific, can be selectively activated in cancer cells to alter endocytic trafficking. Here we report that dynamin isoforms differentially regulate the endocytosis and apoptotic signaling downstream of TNF-related apoptosis-inducing ligand-death receptor (TRAIL-DR) complexes in several cancer cells. Whereas the CME of constitutively internalized transferrin receptors is mainly dependent on the ubiquitously expressed Dyn2, TRAIL-induced DR endocytosis is selectively regulated by activation of Dyn1. We show that TRAIL stimulation activates ryanodine receptor-mediated calcium release from endoplasmic reticulum stores, leading to calcineurin-mediated dephosphorylation and activation of Dyn1, TRAIL-DR endocytosis, and increased resistance to TRAIL-induced apoptosis. TRAIL-DR-mediated ryanodine receptor activation and endocytosis is dependent on early caspase-8 activation. These findings delineate specific mechanisms for the reciprocal crosstalk between signaling and the regulation of CME, leading to autoregulation of endocytosis and signaling downstream of surface receptors.

TRAIL-death receptor endocytosis and apoptosis are selectively regulated by dynamin-1 activation

PubMed Central

Reis, Carlos R.; Chen, Ping-Hung; Bendris, Nawal; Schmid, Sandra L.

2017-01-01

Clathrin-mediated endocytosis (CME) constitutes the major pathway for uptake of signaling receptors into eukaryotic cells. As such, CME regulates signaling from cell-surface receptors, but whether and how specific signaling receptors reciprocally regulate the CME machinery remains an open question. Although best studied for its role in membrane fission, the GTPase dynamin also regulates early stages of CME. We recently reported that dynamin-1 (Dyn1), previously assumed to be neuron-specific, can be selectively activated in cancer cells to alter endocytic trafficking. Here we report that dynamin isoforms differentially regulate the endocytosis and apoptotic signaling downstream of TNF-related apoptosis-inducing ligand–death receptor (TRAIL–DR) complexes in several cancer cells. Whereas the CME of constitutively internalized transferrin receptors is mainly dependent on the ubiquitously expressed Dyn2, TRAIL-induced DR endocytosis is selectively regulated by activation of Dyn1. We show that TRAIL stimulation activates ryanodine receptor-mediated calcium release from endoplasmic reticulum stores, leading to calcineurin-mediated dephosphorylation and activation of Dyn1, TRAIL–DR endocytosis, and increased resistance to TRAIL-induced apoptosis. TRAIL–DR-mediated ryanodine receptor activation and endocytosis is dependent on early caspase-8 activation. These findings delineate specific mechanisms for the reciprocal crosstalk between signaling and the regulation of CME, leading to autoregulation of endocytosis and signaling downstream of surface receptors. PMID:28049841

The machinery of Nod-like receptors: refining the paths to immunity and cell death.

PubMed

Saleh, Maya

2011-09-01

One of the fundamental aspects of the innate immune system is its capacity to discriminate between self and non-self or altered self, and to quickly respond by eliciting effector mechanisms that act in concert to restore normalcy. This capacity is determined by a set of evolutionarily conserved pattern recognition receptors (PRRs) that sense the presence of microbial motifs or endogenous danger signals, including tissue damage, cellular transformation or metabolic perturbation, and orchestrate the nature, duration and intensity of the innate immune response. Nod-like receptors (NLRs), a group of intracellular PRRs, are particularly essential as evident by the high incidence of genetic variations in their genes in various diseases of homeostasis. Here, I overview the signaling mechanisms of NLRs and discuss the mounting evidence of evolutionary conservation between their pathways and the cell death machinery. I also describe their effector functions that link the sensing of danger to the induction of inflammation, autophagy or cell death. © 2011 John Wiley & Sons A/S.

MicroRNA and receptor mediated signaling pathways as potential therapeutic targets in heart failure.

PubMed

Tuttolomondo, Antonino; Simonetta, Irene; Pinto, Antonio

2016-11-01

Cardiac remodelling is a complex pathogenetic pathway involving genome expression, molecular, cellular, and interstitial changes that cause changes in size, shape and function of the heart after cardiac injury. Areas covered: We will review recent advances in understanding the role of several receptor-mediated signaling pathways and micro-RNAs, in addition to their potential as candidate target pathways in the pathogenesis of heart failure. The myocyte is the main target cell involved in the remodelling process via ischemia, cell necrosis and apoptosis (by means of various receptor pathways), and other mechanisms mediated by micro-RNAs. We will analyze the role of some receptor mediated signaling pathways such as natriuretic peptides, mediators of glycogen synthase kinase 3 and ERK1/2 pathways, beta-adrenergic receptor subtypes and relaxin receptor signaling mechanisms, TNF/TNF receptor family and TWEAK/Fn14 axis, and some micro-RNAs as candidate target pathways in pathogenesis of heart failure. These mediators of receptor-mediated pathways and micro-RNA are the most addressed targets of emerging therapies in modern heart failure treatment strategies. Expert opinion: Future treatment strategies should address mediators involved in multiple steps within heart failure pathogenetic pathways.

Emerging Paradigm of Intracellular Targeting of G Protein-Coupled Receptors.

PubMed

Chaturvedi, Madhu; Schilling, Justin; Beautrait, Alexandre; Bouvier, Michel; Benovic, Jeffrey L; Shukla, Arun K

2018-05-04

G protein-coupled receptors (GPCRs) recognize a diverse array of extracellular stimuli, and they mediate a broad repertoire of signaling events involved in human physiology. Although the major effort on targeting GPCRs has typically been focused on their extracellular surface, a series of recent developments now unfold the possibility of targeting them from the intracellular side as well. Allosteric modulators binding to the cytoplasmic surface of GPCRs have now been described, and their structural mechanisms are elucidated by high-resolution crystal structures. Furthermore, pepducins, aptamers, and intrabodies targeting the intracellular face of GPCRs have also been successfully utilized to modulate receptor signaling. Moreover, small molecule compounds, aptamers, and synthetic intrabodies targeting β-arrestins have also been discovered to modulate GPCR endocytosis and signaling. Here, we discuss the emerging paradigm of intracellular targeting of GPCRs, and outline the current challenges, potential opportunities, and future outlook in this particular area of GPCR biology. Copyright © 2018 Elsevier Ltd. All rights reserved.

Selective targeting of G-protein-coupled receptor subtypes with venom peptides.

PubMed

Näreoja, K; Näsman, J

2012-02-01

The G-protein-coupled receptor (GPCR) family is one of the largest gene superfamilies with approx. 370 members responding to endogenous ligands in humans and a roughly equal amount of receptors sensitive to external stimuli from the surrounding. A number of receptors from this superfamily are well recognized targets for medical treatment of various disease conditions, whereas for many others the potential medical benefit of interference is still obscure. A general problem associated with GPCR research and therapeutics is the insufficient specificity of available ligands to differentiate between closely homologous receptor subtypes. In this context, venom peptides could make a significant contribution to the development of more specific drugs. Venoms from certain animals specialized in biochemical hunting contain a mixture of molecules that are directed towards a variety of membrane proteins. Peptide toxins isolated from these mixtures usually exhibit high specificity for their targets. Muscarinic toxins found from mamba snakes attracted much attention during the 1990s. These are 65-66 amino acid long peptides with a structural three-finger folding similar to the α-neurotoxins and they target the muscarinic acetylcholine receptors in a subtype-selective manner. Recently, several members of the three-finger toxins from mamba snakes as well as conotoxins from marine cone snails have been shown to selectively interact with subtypes of adrenergic receptors. In this review, we will discuss the GPCR-directed peptide toxins found from different venoms and how some of these can be useful in exploring specific roles of receptor subtypes. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.

Lipid-Polymer Nanoparticles for Folate-Receptor Targeting Delivery of Doxorubicin.

PubMed

Zheng, Mingbin; Gong, Ping; Zheng, Cuifang; Zhao, Pengfei; Luo, Zhenyu; Ma, Yifan; Cai, Lintao

2015-07-01

A biocompatible PLGA-lipid hybrid nanoparticles (NPs) was developed for targeted delivery of anticancer drugs with doxorubicin (DOX). The hydrodynamic diameter and zeta potential of DOX-loaded PLGA-lipid NPs (DNPs) were affected by the mass ratio of Lipid/PLGA or DSPE-PEG-COOH/Lecithin. At the 1:20 drug/polymer mass ratio, the mean hydrodynamic diameter of DNPs was the lowest (99.2 1.83 nm) and the NPs presented the encapsulation efficiency of DOX with 42.69 1.30%. Due to the folate-receptor mediated endocytosis, the PLGA-lipid NPs with folic acid (FA) targeting ligand showed significant higher uptake by folate-receptor-positive MCF-7 cells as compared to PLGA-lipid NPs without folate. Confocal microscopic observation and flow cytometry analysis also supported the enhanced cellular uptake of the FA-targeted NPs. The results indicated that the FA-targeted DNPs exhibited higher cytotoxicity in MCF-7 cells compared with non-targeted NPs. The lipid-polymer nanoparticles provide a solution of biocompatible nanocarrier for cancer targeting therapy.

Insect odorant receptors are molecular targets of the insect repellent DEET.

PubMed

Ditzen, Mathias; Pellegrino, Maurizio; Vosshall, Leslie B

2008-03-28

DEET (N,N-diethyl-meta-toluamide) is the world's most widely used topical insect repellent, with broad effectiveness against most insects. Its mechanism of action and molecular target remain unknown. Here, we show that DEET blocks electrophysiological responses of olfactory sensory neurons to attractive odors in Anopheles gambiae and Drosophila melanogaster. DEET inhibits behavioral attraction to food odors in Drosophila, and this inhibition requires the highly conserved olfactory co-receptor OR83b. DEET inhibits odor-evoked currents mediated by the insect odorant receptor complex, comprising a ligand-binding subunit and OR83b. We conclude that DEET masks host odor by inhibiting subsets of heteromeric insect odorant receptors that require the OR83b co-receptor. The identification of candidate molecular targets for the action of DEET may aid in the design of safer and more effective insect repellents.

Blocking NMDA receptors delays death in rats with acute liver failure by dual protective mechanisms in kidney and brain.

PubMed

Cauli, Omar; González-Usano, Alba; Cabrera-Pastor, Andrea; Gimenez-Garzó, Carla; López-Larrubia, Pilar; Ruiz-Sauri, Amparo; Hernández-Rabaza, Vicente; Duszczyk, Malgorzata; Malek, Michal; Lazarewicz, Jerzy W; Carratalá, Arturo; Urios, Amparo; Miguel, Alfonso; Torregrosa, Isidro; Carda, Carmen; Montoliu, Carmina; Felipo, Vicente

2014-06-01

Treatment of patients with acute liver failure (ALF) is unsatisfactory and mortality remains unacceptably high. Blocking NMDA receptors delays or prevents death of rats with ALF. The underlying mechanisms remain unclear. Clarifying these mechanisms will help to design more efficient treatments to increase patient's survival. The aim of this work was to shed light on the mechanisms by which blocking NMDA receptors delays rat's death in ALF. ALF was induced by galactosamine injection. NMDA receptors were blocked by continuous MK-801 administration. Edema and cerebral blood flow were assessed by magnetic resonance. The time course of ammonia levels in brain, muscle, blood, and urine; of glutamine, lactate, and water content in brain; of glomerular filtration rate and kidney damage; and of hepatic encephalopathy (HE) and intracranial pressure was assessed. ALF reduces kidney glomerular filtration rate (GFR) as reflected by reduced inulin clearance. GFR reduction is due to both reduced renal perfusion and kidney tubular damage as reflected by increased Kim-1 in urine and histological analysis. Blocking NMDA receptors delays kidney damage, allowing transient increased GFR and ammonia elimination which delays hyperammonemia and associated changes in brain. Blocking NMDA receptors does not prevent cerebral edema or blood-brain barrier permeability but reduces or prevents changes in cerebral blood flow and brain lactate. The data show that dual protective effects of MK-801 in kidney and brain delay cerebral alterations, HE, intracranial pressure increase and death. NMDA receptors antagonists may increase survival of patients with ALF by providing additional time for liver transplantation or regeneration.

Structural basis of death domain signaling in the p75 neurotrophin receptor

PubMed Central

Lin, Zhi; Tann, Jason Y; Goh, Eddy TH; Kelly, Claire; Lim, Kim Buay; Gao, Jian Fang; Ibanez, Carlos F

2015-01-01

Death domains (DDs) mediate assembly of oligomeric complexes for activation of downstream signaling pathways through incompletely understood mechanisms. Here we report structures of complexes formed by the DD of p75 neurotrophin receptor (p75NTR) with RhoGDI, for activation of the RhoA pathway, with caspase recruitment domain (CARD) of RIP2 kinase, for activation of the NF-kB pathway, and with itself, revealing how DD dimerization controls access of intracellular effectors to the receptor. RIP2 CARD and RhoGDI bind to p75NTR DD at partially overlapping epitopes with over 100-fold difference in affinity, revealing the mechanism by which RIP2 recruitment displaces RhoGDI upon ligand binding. The p75NTR DD forms non-covalent, low-affinity symmetric dimers in solution. The dimer interface overlaps with RIP2 CARD but not RhoGDI binding sites, supporting a model of receptor activation triggered by separation of DDs. These structures reveal how competitive protein-protein interactions orchestrate the hierarchical activation of downstream pathways in non-catalytic receptors. DOI: http://dx.doi.org/10.7554/eLife.11692.001 PMID:26646181

Cardio-oncology Related to Heart Failure: Epidermal Growth Factor Receptor Target-Based Therapy.

PubMed

Kenigsberg, Benjamin; Jain, Varun; Barac, Ana

2017-04-01

Cancer therapy targeting the epidermal growth factor receptor (EGFR)/erythroblastic leukemia viral oncogene B (ErbB)/human EGFR receptor (HER) family of tyrosine kinases has been successfully used in treatment of several malignancies. The ErbB pathways play a role in the maintenance of cardiac homeostasis. This article summarizes current knowledge about EGFR/ErbB/HER receptor-targeted cancer therapeutics focusing on their cardiotoxicity profiles, molecular mechanisms, and implications in clinical cardio-oncology. The article discusses challenges in predicting, monitoring, and treating cardiac dysfunction and heart failure associated with ErbB-targeted cancer therapeutics and highlights opportunities for researchers and clinical investigators. Copyright © 2016 Elsevier Inc. All rights reserved.

Toll-like Receptor 3 (TLR3) Induces Apoptosis via Death Receptors and Mitochondria by Up-regulating the Transactivating p63 Isoform α (TAP63α)*

PubMed Central

Sun, Ruili; Zhang, Yu; Lv, Qingshan; Liu, Bei; Jin, Miao; Zhang, Weijia; He, Qing; Deng, Minjie; Liu, Xueting; Li, Guancheng; Li, Yuehui; Zhou, Guohua; Xie, Pingli; Xie, Xiumei; Hu, Jinyue; Duan, Zhaojun

2011-01-01

Toll-like receptor 3 (TLR3), a member of the pathogen recognition receptors, is widely expressed in various cells and has been shown to activate immune signaling pathways by recognizing viral double-stranded RNA. Recently, it was reported that the activation of TLR3 induced apoptosis in some cells, but the detailed molecular mechanism is not fully understood. In this study, we found that in endothelial cells polyinosinic-polycytidylic acid (poly(I-C)) induced dose- and time-dependent cell apoptosis, which was elicited by TLR3 activation, as TLR3 neutralization and down-regulation repressed the apoptosis. Poly(I-C) induced the activation of both caspases 8 and 9, indicating that TLR3 triggered the signaling of both the extrinsic and intrinsic apoptotic pathways. Poly(I-C) up-regulated tumor necrosis factor-related apoptosis-inducing ligand and its receptors, death receptors 4/5, resulting in initiating the extrinsic pathway. Furthermore, poly(I-C) down-regulated anti-apoptotic protein, B cell lymphoma 2 (Bcl-2), and up-regulated Noxa, a key Bcl-2 homology 3-only antagonist of Bcl-2, leading to the priming of the intrinsic pathway. A p53-related protein, the transactivating p63 isoform α (TAp63α), was induced by TLR3 activation and contributed to the activation of both the intrinsic and extrinsic apoptotic pathways. Both the cells deficient in p63 gene expression by RNA interference and cells that overexpressed the N-terminally truncated p63 isoform α (ΔNp63α), a dominant-negative variant of TAp63α, by gene transfection, survived TLR3 activation. Taken together, TAp63α is a crucial regulator downstream of TLR3 to induce cell death via death receptors and mitochondria. PMID:21367858

Dependence receptors: the dark side awakens.

PubMed

Negulescu, Ana-Maria; Mehlen, Patrick

2018-05-18

Transmembrane receptors are usually seen as on and off switch: when the specific ligand is bound, the receptor is on and transduces a downstream signal, while when the ligand is absent, the receptor is off. Over the last two decades several reports have argued from an alternative view where some receptors, depending on the context, will be active both in the presence and in the absence of ligand, being sort of on A and on B switch rather than on and off. These receptors have been named Dependence Receptors (DR) and they share the ability to actively trigger cell death when unbound by their respective ligands. DRs have been shown to be important guardians of tissue homeostasis. In pathological settings such as cancer, DRs are seen as tumor suppressors and a clinical trial is ongoing to assay whether these DRs can be used to provide clinical benefit by triggering cancer cell death. In this review we are reviewing this functional family of receptors and underlying their promising potential for targeted therapy against cancer. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Defective lysosomal targeting of activated fibroblast growth factor receptor 3 in achondroplasia.

PubMed

Cho, Jay Y; Guo, Changsheng; Torello, Monica; Lunstrum, Gregory P; Iwata, Tomoko; Deng, Chuxia; Horton, William A

2004-01-13

Mutations of fibroblast growth factor receptor 3 (FGFR3) are responsible for achondroplasia (ACH) and related dwarfing conditions in humans. The pathogenesis involves constitutive activation of FGFR3, which inhibits proliferation and differentiation of growth plate chondrocytes. Here we report that activating mutations in FGFR3 increase the stability of the receptor. Our results suggest that the mutations disrupt c-Cbl-mediated ubiquitination that serves as a targeting signal for lysosomal degradation and termination of receptor signaling. The defect allows diversion of actively signaling receptors from lysosomes to a recycling pathway where their survival is prolonged, and, as a result, their signaling capacity is increased. The lysosomal targeting defect is additive to other mechanisms proposed to explain the pathogenesis of ACH.

Pharmacological approaches to targeting muscarinic acetylcholine receptors.

PubMed

Matera, Carlo; Tata, Ada M

2014-01-01

The presence of cholinergic system markers and muscarinic receptor subtypes in several tissues also of nonneuronal type has been largely demonstrated. Acetylcholine, synthesized in the nervous system, can locally contribute to modulate cell proliferation, survival and apoptosis. Considering that the cholinergic system functions are impaired in a number of disorders, the identification of new drugs regulating these functions appears of great clinical relevance. The possible involvement of muscarinic acetylcholine receptors in different pathologies has been proposed in recent years and is becoming an important area of study. However, the lack of selective muscarinic receptor ligands has for long time limited the therapeutic treatment based on muscarinic receptors as targets. To date, some muscarinic ligands such as xanomeline (patent, US5980933) or cevimeline (patents US4855290, US5571918) have been developed for the treatment of several pathologies (Alzheimer's and Sjogren's diseases). The present review will be focused on the potential effects produced by muscarinic receptor activation in different pathologies, including tumors. In fact, the potential use of muscarinic ligands in therapeutic protocols in cancer therapy will be discussed, considering that several muscarinic antagonists, already used in the treatment of genitourinary diseases (e.g. darifenacin, patent, US5096890, US6106864), have also been demonstrated to arrest the tumor growth in vivo. Moreover, the contribution of muscarinic receptors to analgesia is also reviewed. Finally, some of the most significant achievements in the field of bitopic/dualsteric ligands will be discussed and the molecules patented so far will be presented.

Transient receptor potential canonical 4 and 5 proteins as targets in cancer therapeutics.

PubMed

Gaunt, Hannah J; Vasudev, Naveen S; Beech, David J

2016-10-01

Novel approaches towards cancer therapy are urgently needed. One approach might be to target ion channels mediating Ca 2+ entry because of the critical roles played by Ca 2+ in many cell types, including cancer cells. There are several types of these ion channels, but here we address those formed by assembly of transient receptor potential canonical (TRPC) proteins, particularly those which involve two closely related members of the family: TRPC4 and TRPC5. We focus on these proteins because recent studies point to roles in important aspects of cancer: drug resistance, transmission of drug resistance through extracellular vesicles, tumour vascularisation, and evoked cancer cell death by the TRPC4/5 channel activator (-)-englerin A. We conclude that further research is both justified and necessary before these proteins can be considered as strong targets for anti-cancer cell drug discovery programmes. It is nevertheless already apparent that inhibitors of the channels would be unlikely to cause significant adverse effects, but, rather, have other effects which may be beneficial in the context of cancer and chemotherapy, potentially including suppression of innate fear, visceral pain and pathological cardiac remodelling.

An endogenous 55 kDa TNF receptor mediates cell death in a neural cell line.

PubMed

Sipe, K J; Srisawasdi, D; Dantzer, R; Kelley, K W; Weyhenmeyer, J A

1996-06-01

Tumor necrosis factor-alpha (TNF) is associated with developmental and injury-related events in the central nervous system (CNS). In the present study, we have examined the role of TNF on neurons using the clonal murine neuroblastoma line, N1E-115 (N1E). N1E cells represent a well-defined model for studying neuronal development since they can be maintained as either undifferentiated, mitotically active neuroblasts or as differentiated, mature neurons. Northern and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that both undifferentiated and differentiated N1Es express transcripts for the 55 kDa TNF receptor (TNFR), but not the 75 kDa TNFR. The biological activity of the expressed TNF receptor was demonstrated by a dose dependent cytotoxicity to either recombinant murine or human TNF when the cells were incubated with the transcriptional inhibitor actinomycin D. The lack of the 75 kDa receptor mRNA expression and the dose dependent response to rHuTNF, an agonist specific for the murine 55 kDa receptor, suggest that the TNF induced cytotoxicity is mediated through the 55 kDa receptor in both the undifferentiated and differentiated N1Es. Light microscopic observations, flow cytometric analysis of hypodiploid DNA, and electrophoretic analysis of nucleosomal DNA fragmentation of N1Es treated with actinomycin D and TNF revealed features characteristic of both necrotic and apoptotic cell death. These findings demonstrate that blast and mature N1E cells express the 55 kDa TNF receptor which is responsible for inducing both necrotic and apoptotic death in these cells. The observation that actinomycin D renders N1E cells susceptible to the cytotoxic effects of TNF indicates that a sensitization step, such as removal of an endogenous protective factor or viral-mediated inhibition of transcription, may be necessary for TNF cytotoxicity in neurons.

Soluble Tumor Necrosis Factor Alpha Promotes Retinal Ganglion Cell Death in Glaucoma via Calcium-Permeable AMPA Receptor Activation.

PubMed

Cueva Vargas, Jorge L; Osswald, Ingrid K; Unsain, Nicolas; Aurousseau, Mark R; Barker, Philip A; Bowie, Derek; Di Polo, Adriana

2015-09-02

Loss of vision in glaucoma results from the selective death of retinal ganglion cells (RGCs). Tumor necrosis factor α (TNFα) signaling has been linked to RGC damage, however, the mechanism by which TNFα promotes neuronal death remains poorly defined. Using an in vivo rat glaucoma model, we show that TNFα is upregulated by Müller cells and microglia/macrophages soon after induction of ocular hypertension. Administration of XPro1595, a selective inhibitor of soluble TNFα, effectively protects RGC soma and axons. Using cobalt permeability assays, we further demonstrate that endogenous soluble TNFα triggers the upregulation of Ca(2+)-permeable AMPA receptor (CP-AMPAR) expression in RGCs of glaucomatous eyes. CP-AMPAR activation is not caused by defects in GluA2 subunit mRNA editing, but rather reflects selective downregulation of GluA2 in neurons exposed to elevated eye pressure. Intraocular administration of selective CP-AMPAR blockers promotes robust RGC survival supporting a critical role for non-NMDA glutamate receptors in neuronal death. Our study identifies glia-derived soluble TNFα as a major inducer of RGC death through activation of CP-AMPARs, thereby establishing a novel link between neuroinflammation and cell loss in glaucoma. Tumor necrosis factor α (TNFα) has been implicated in retinal ganglion cell (RGC) death, but how TNFα exerts this effect is poorly understood. We report that ocular hypertension, a major risk factor in glaucoma, upregulates TNFα production by Müller cells and microglia. Inhibition of soluble TNFα using a dominant-negative strategy effectively promotes RGC survival. We find that TNFα stimulates the expression of calcium-permeable AMPA receptors (CP-AMPAR) in RGCs, a response that does not depend on abnormal GluA2 mRNA editing but on selective downregulation of the GluA2 subunit by these neurons. Consistent with this, CP-AMPAR blockers promote robust RGC survival supporting a critical role for non-NMDA glutamate receptors

Targeting IL11 Receptor in Leukemia and Lymphoma: A Functional Ligand-Directed Study and Hematopathology Analysis of Patient-Derived Specimens.

PubMed

Karjalainen, Katja; Jaalouk, Diana E; Bueso-Ramos, Carlos; Bover, Laura; Sun, Yan; Kuniyasu, Akihiko; Driessen, Wouter H P; Cardó-Vila, Marina; Rietz, Cecilia; Zurita, Amado J; O'Brien, Susan; Kantarjian, Hagop M; Cortes, Jorge E; Calin, George A; Koivunen, Erkki; Arap, Wadih; Pasqualini, Renata

2015-07-01

The IL11 receptor (IL11R) is an established molecular target in primary tumors of bone, such as osteosarcoma, and in secondary bone metastases from solid tumors, such as prostate cancer. However, its potential role in management of hematopoietic malignancies has not yet been determined. Here, we evaluated the IL11R as a candidate therapeutic target in human leukemia and lymphoma. First, we show that the IL11R protein is expressed in a variety of human leukemia- and lymphoma-derived cell lines and in a large panel of bone marrow samples from leukemia and lymphoma patients, whereas expression is absent from nonmalignant control bone marrow. Moreover, a targeted peptidomimetic prototype (termed BMTP-11), specifically bound to leukemia and lymphoma cell membranes, induced ligand-receptor internalization mediated by the IL11R, and resulted in a specific dose-dependent cell death induction in these cells. Finally, a pilot drug lead-optimization program yielded a new myristoylated BMTP-11 analogue with an apparent improved antileukemia cell profile. These results indicate (i) that the IL11R is a suitable cell surface target for ligand-directed applications in human leukemia and lymphoma and (ii) that BMTP-11 and its derivatives have translational potential against this group of malignant diseases. ©2015 American Association for Cancer Research.

Targeting interleukin-11 receptor in leukemia and lymphoma: A functional ligand-directed study and hematopathology analysis of patient-derived specimens

PubMed Central

Karjalainen, Katja; Jaalouk, Diana E.; Bueso-Ramos, Carlos; Bover, Laura; Sun, Yan; Kuniyasu, Akihiko; Driessen, Wouter H. P.; Cardó-Vila, Marina; Rietz, Cecilia; Zurita, Amado J.; O’Brien, Susan; Kantarjian, Hagop M.; Cortes, Jorge E.; Calin, George A.; Koivunen, Erkki; Arap, Wadih; Pasqualini, Renata

2015-01-01

Purpose The interleukin-11 receptor (IL-11R) is an established molecular target in primary tumors of bone, such as osteosarcoma, and in secondary bone metastases from solid tumors such as prostate cancer. However, its potential role in management of hematopoietic malignancies has not yet been determined. Here we evaluated the IL-11R as a candidate therapeutic target in human leukemia and lymphoma. Experimental Design and Results First, we show that the IL-11R protein is expressed in a variety of human leukemia- and lymphoma derived cell lines and in a large panel of bone marrow samples from leukemia and lymphoma patients, while expression is absent from non-malignant control bone marrow. Moreover, a targeted peptidomimetic prototype (termed BMTP-11) specifically bound to leukemia and lymphoma cell membranes, induced ligand-receptor internalization mediated by the IL-11R, and resulted in a specific dose-dependent cell death induction in these cells. Finally, a pilot drug lead-optimization program yielded a new myristoylated BMTP-11 analog with an apparent improved anti-leukemia cell profile. Conclusion These results indicate (i) that the IL-11R is a suitable cell surface target for ligand-directed applications in human leukemia and lymphoma and (ii) that BMTP-11 and its derivatives have translational potential against this group of malignant diseases. PMID:25779950

Transcriptional targets shared by estrogen receptor- related receptors (ERRs) and estrogen receptor (ER) alpha, but not by ERbeta.

PubMed Central

Vanacker, J M; Pettersson, K; Gustafsson, J A; Laudet, V

1999-01-01

The physiological activities of estrogens are thought to be mediated by specific nuclear receptors, ERalpha and ERbeta. However, certain tissues, such as the bone, that are highly responsive to estrogens only express a low level of these receptors. Starting from this apparent contradiction, we have evaluated the potentials of two related receptors ERRalpha and ERRbeta to intervene in estrogen signaling. ERalpha, ERRalpha and ERRbeta bind to and activate transcription through both the classical estrogen response element (ERE) and the SF-1 response element (SFRE). In contrast, ERbeta DNA-binding and transcriptional activity is restricted to the ERE. Accordingly, the osteopontin gene promoter is stimulated through SFRE sequences, by ERRalpha as well as by ERalpha, but not by ERbeta. Analysis of the cross-talk within the ER/ERR subgroup of nuclear receptors thus revealed common targets but also functional differences between the two ERs. PMID:10428965

Hyaluronan-decorated polymer nanoparticles targeting the CD44 receptor for the combined photo/chemo-therapy of cancer

NASA Astrophysics Data System (ADS)

Maiolino, Sara; Moret, Francesca; Conte, Claudia; Fraix, Aurore; Tirino, Pasquale; Ungaro, Francesca; Sortino, Salvatore; Reddi, Elena; Quaglia, Fabiana

2015-03-01

In the attempt to develop novel concepts in designing targeted nanoparticles for combination therapy of cancer, we propose here CD44-targeted hyaluronan-decorated double-coated nanoparticles (dcNPs) delivering the lipophilic chemotherapeutic docetaxel (DTX) and an anionic porphyrin (TPPS4). dcNPs are based on electrostatic interactions between a negative DTX-loaded nanoscaffold of poly(lactide-co-glycolide), a polycationic shell of polyethyleneimine entangling negatively-charged TPPS4 and finally decorated with hyaluronan (HA) to promote internalization through CD44 receptor-mediated endocytosis. DTX/TPPS4-dcNPs, prepared through layer-by-layer deposition, showed a hydrodynamic diameter of around 180 nm, negative zeta potential and efficient loading of both DTX and TPPS4. DTX/TPPS4-dcNPs were freeze-dried with trehalose giving a powder that could be easily dispersed in different media. Excellent stability of dcNPs in specific salt- and protein-containing media was found. Spectroscopic behavior of DTX/TPPS4-dcNPs demonstrated a face-to-face arrangement of the TPPS4 units in non-photoresponsive H-type aggregates accounting for an extensive aggregation of the porphyrin embedded in the shell. Experiments in MDA-MB-231 cells overexpressing the CD44 receptor demonstrated a 9.4-fold increase in the intracellular level of TPPS4 delivered from dcNPs as compared to free TPPS4. Light-induced death increased tremendously in cells that had been treated with a combination of TPPS4 and DTX delivered through dcNPs as compared with free drugs, presumably due to efficient uptake and co-localization inside the cells. In perspective, the strategy proposed here to target synergistic drug combinations through HA-decorated nanoparticles seems very attractive to improve the specificity and efficacy of cancer treatment.In the attempt to develop novel concepts in designing targeted nanoparticles for combination therapy of cancer, we propose here CD44-targeted hyaluronan-decorated double

Targeting PYK2 mediates microenvironment-specific cell death in multiple myeloma

PubMed Central

Meads, MB; Fang, B; Mathews, L; Gemmer, J; Nong, L; Rosado-Lopez, I; Nguyen, T; Ring, JE; Matsui, W; MacLeod, AR; Pachter, JA; Hazlehurst, LA; Koomen, JM; Shain, KH

2015-01-01

Multiple myeloma (MM) remains an incurable malignancy due, in part, to the influence of the bone marrow microenvironment on survival and drug response. Identification of microenvironment-specific survival signaling determinants is critical for the rational design of therapy and elimination of MM. Previously, we have shown that collaborative signaling between β1 integrin-mediated adhesion to fibronectin and interleukin-6 confers a more malignant phenotype via amplification of signal transducer and activator of transcription 3 (STAT3) activation. Further characterization of the events modulated under these conditions with quantitative phosphotyrosine profiling identified 193 differentially phosphorylated peptides. Seventy-seven phosphorylations were upregulated upon adhesion, including PYK2/FAK2, Paxillin, CASL and p130CAS consistent with focal adhesion (FA) formation. We hypothesized that the collaborative signaling between β1 integrin and gp130 (IL-6 beta receptor, IL-6 signal transducer) was mediated by FA formation and proline-rich tyrosine kinase 2 (PYK2) activity. Both pharmacological and molecular targeting of PYK2 attenuated the amplification of STAT3 phosphorylation under co-stimulatory conditions. Co-culture of MM cells with patient bone marrow stromal cells (BMSC) showed similar β1 integrin-specific enhancement of PYK2 and STAT3 signaling. Molecular and pharmacological targeting of PYK2 specifically induced cell death and reduced clonogenic growth in BMSC-adherent myeloma cell lines, aldehyde dehydrogenase-positive MM cancer stem cells and patient specimens. Finally, PYK2 inhibition similarly attenuated MM progression in vivo. These data identify a novel PYK2-mediated survival pathway in MM cells and MM cancer stem cells within the context of microenvironmental cues, providing preclinical support for the use of the clinical stage FAK/PYK2 inhibitors for treatment of MM, especially in a minimal residual disease setting. PMID:26387544

Specific Retrograde Transduction of Spinal Motor Neurons Using Lentiviral Vectors Targeted to Presynaptic NMJ Receptors

PubMed Central

Eleftheriadou, I; Trabalza, A; Ellison, SM; Gharun, K; Mazarakis, ND

2014-01-01

To understand how receptors are involved in neuronal trafficking and to be able to utilize them for specific targeting via the peripheral route would be of great benefit. Here, we describe the generation of novel lentiviral vectors with tropism to motor neurons that were made by coexpressing onto the lentiviral surface a fusogenic glycoprotein (mutated sindbis G) and an antibody against a cell-surface receptor (Thy1.1, p75NTR, or coxsackievirus and adenovirus receptor) on the presynaptic terminal of the neuromuscular junction. These vectors exhibit binding specificity and efficient transduction of receptor positive cell lines and primary motor neurons in vitro. Targeting of each of these receptors conferred to these vectors the capability of being transported retrogradely from the axonal tip, leading to transduction of motor neurons in vitro in compartmented microfluidic cultures. In vivo delivery of coxsackievirus and adenovirus receptor-targeted vectors in leg muscles of mice resulted in predicted patterns of motor neuron labeling in lumbar spinal cord. This opens up the clinical potential of these vectors for minimally invasive administration of central nervous system-targeted therapeutics in motor neuron diseases. PMID:24670531

Targeting of TAM Receptors Ameliorates Fibrotic Mechanisms in Idiopathic Pulmonary Fibrosis.

PubMed

Espindola, Milena S; Habiel, David M; Narayanan, Rohan; Jones, Isabelle; Coelho, Ana L; Murray, Lynne A; Jiang, Dianhua; Noble, Paul W; Hogaboam, Cory M

2018-06-01

Idiopathic pulmonary fibrosis (IPF) is characterized by aberrant lung remodeling, which progressively abolishes lung function in an RTK (receptor tyrosine kinase)-dependent manner. Gas6 (growth arrest-specific 6) ligand, Tyro3 (TYRO3 protein tyrosine kinase 3), and Axl (anexelekto) RTK expression and activity are increased in IPF. To determine if targeting these RTK pathways would inhibit fibroblast activation and the development of pulmonary fibrosis. Quantitative genomic, proteomic, and functional analyses were used to determine Gas6/TAM (Tyro3, Axl, and Mertk [MER proto-oncogene, tyrosine kinase]) RTK expression and activation in tissues and fibroblasts from normal and IPF lungs. The profibrotic impact of these RTK pathways were also examined in bleomycin-induced pulmonary fibrosis and in SCID/Bg mice that developed pulmonary fibrosis after the intravenous administration of primary IPF fibroblasts. Gas6, Axl, and Tyro3 were increased in both rapidly and slowly progressive IPF compared with normal lung samples and fibroblasts. Targeting these pathways with either specific antibodies directed at Gas6 or Axl, or with small-molecule TAM inhibitors indicated that the small molecule-mediated targeting approach was more efficacious in both in vitro and in vivo studies. Specifically, the TAM receptor inhibitor R428 (also known as BGB324) significantly inhibited the synthetic, migratory, and proliferative properties of IPF fibroblasts compared with the other Gas6/TAM receptor targeting agents. Finally, loss of Gas6 expression decreased lung fibrotic responses to bleomycin and treatment with R428 inhibited pulmonary fibrosis in humanized SCID/Bg mice. Gas6/TAM receptor activity contributes to the activation of pulmonary fibroblasts in IPF, suggesting that targeting this RTK pathway might be an effective antifibrotic strategy in this disease.

Receptor-Targeted Nanoparticles for In Vivo Imaging of Breast Cancer

PubMed Central

Yang, Lily; Peng, Xiang-Hong; Wang, Y. Andrew; Wang, Xiaoxia; Cao, Zehong; Ni, Chunchun; Karna, Prasanthi; Zhang, Xinjian; Wood, William C.; Gao, Xiaohu; Nie, Shuming; Mao, Hui

2009-01-01

Purpose Cell surface receptor-targeted magnetic iron oxide (IO) nanoparticles provide molecular magnetic resonance imaging (MRI) contrast agents for improving specificity of the detection of human cancer. Experimental design The present study reports the development of a novel targeted IO nanoparticle using a recombinant peptide containing the amino-terminal fragment (ATF) of urokinase plasminogen activator conjugated to IO nanoparticles (ATF-IO). This nanoparticle targets urokinase plasminogen activator receptor (uPAR), which is overexpressed in breast cancer tissues. Results ATF-IO nanoparticles are able to specifically bind to and be internalized by uPAR-expressing tumor cells. Systemic delivery of ATF-IO nanoparticles into mice bearing subcutaneous and intraperitoneal mammary tumors leads to the accumulation of the particles in tumors, generating a strong MRI contrast detectable by a clinical MRI scanner at a field strength of 3 Tesla. Target specificity of ATF-IO nanoparticles demonstrated by in vivo MRI is further confirmed by near infrared (NIR) fluorescence imaging of the mammary tumors using NIR dye-labeled ATF peptides conjugated to IO nanoparticles. Furthermore, mice administered ATF-IO nanoparticles exhibit lower uptake of the particles in the liver and spleen compared to those receiving non-targeted IO nanoparticles. Conclusions Our results suggest that uPAR-targeted ATF-IO nanoparticles have potential as molecularly-targeted, dual modality imaging agents for in vivo imaging of breast cancer. PMID:19584158

Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro

PubMed Central

Kaushal, Nidhi; Robson, Matthew J.; Rosen, Abagail; McCurdy, Christopher R.; Matsumoto, Rae R.

2014-01-01

Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3,-8 and-9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 °C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 °C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 °C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

Current drug treatments targeting dopamine D3 receptor.

PubMed

Leggio, Gian Marco; Bucolo, Claudio; Platania, Chiara Bianca Maria; Salomone, Salvatore; Drago, Filippo

2016-09-01

Dopamine receptors (DR) have been extensively studied, but only in recent years they became object of investigation to elucidate the specific role of different subtypes (D1R, D2R, D3R, D4R, D5R) in neural transmission and circuitry. D1-like receptors (D1R and D5R) and D2-like receptors (D2R, D2R and D4R) differ in signal transduction, binding profile, localization in the central nervous system and physiological effects. D3R is involved in a number of pathological conditions, including schizophrenia, Parkinson's disease, addiction, anxiety, depression and glaucoma. Development of selective D3R ligands has been so far challenging, due to the high sequence identity and homology shared by D2R and D3R. As a consequence, despite a rational design of selective DR ligands has been carried out, none of currently available medicines selectively target a given D2-like receptor subtype. The availability of the D3R ligand [(11)C]-(+)-PHNO for positron emission tomography studies in animal models as well as in humans, allows researchers to estimate the expression of D3R in vivo; displacement of [(11)C]-(+)-PHNO binding by concurrent drug treatments is used to estimate the in vivo occupancy of D3R. Here we provide an overview of studies indicating D3R as a target for pharmacological therapy, and a review of market approved drugs endowed with significant affinity at D3R that are used to treat disorders where D3R plays a relevant role. Copyright © 2016 Elsevier Inc. All rights reserved.

Decreased circulation time offsets increased efficacy of PEGylated nanocarriers targeting folate receptors of glioma

NASA Astrophysics Data System (ADS)

McNeeley, Kathleen M.; Annapragada, Ananth; Bellamkonda, Ravi V.

2007-09-01

Liposomal and other nanocarrier based drug delivery vehicles can localize to tumours through passive and/or active targeting. Passively targeted liposomal nanocarriers accumulate in tumours via 'leaky' vasculature through the enhanced permeability and retention (EPR) effect. Passive accumulation depends upon the circulation time and the degree of tumour vessel 'leakiness'. After extravasation, actively targeted liposomal nanocarriers efficiently deliver their payload by receptor-mediated uptake. However, incorporation of targeting moieties can compromise circulation time in the blood due to recognition and clearance by the reticuloendothelial system, decreasing passive accumulation. Here, we compare the efficacy of passively targeted doxorubicin-loaded PEGylated liposomal nanocarriers to that of actively targeted liposomal nanocarriers in a rat 9L brain tumour model. Although folate receptor (FR)-targeted liposomal nanocarriers had significantly reduced blood circulation time compared to PEGylated liposomal nanocarriers; intratumoural drug concentrations both at 20 and 50 h after administration were equal for both treatments. Both treatments significantly increased tumour inoculated animal survival by 60-80% compared to non-treated controls, but no difference in survival was observed between FR-targeted and passively targeted nanocarriers. Therefore, alternate approaches allowing for active targeting without compromising circulation time may be important for fully realizing the benefits of receptor-mediated active targeting of gliomas.

Targeting fibroblast growth factor receptor signaling inhibits prostate cancer progression.

PubMed

Feng, Shu; Shao, Longjiang; Yu, Wendong; Gavine, Paul; Ittmann, Michael

2012-07-15

Extensive correlative studies in human prostate cancer as well as studies in vitro and in mouse models indicate that fibroblast growth factor receptor (FGFR) signaling plays an important role in prostate cancer progression. In this study, we used a probe compound for an FGFR inhibitor, which potently inhibits FGFR-1-3 and significantly inhibits FGFR-4. The purpose of this study is to determine whether targeting FGFR signaling from all four FGFRs will have in vitro activities consistent with inhibition of tumor progression and will inhibit tumor progression in vivo. Effects of AZ8010 on FGFR signaling and invasion were analyzed using immortalized normal prostate epithelial (PNT1a) cells and PNT1a overexpressing FGFR-1 or FGFR-4. The effect of AZ8010 on invasion and proliferation in vitro was also evaluated in prostate cancer cell lines. Finally, the impact of AZ8010 on tumor progression in vivo was evaluated using a VCaP xenograft model. AZ8010 completely inhibits FGFR-1 and significantly inhibits FGFR-4 signaling at 100 nmol/L, which is an achievable in vivo concentration. This results in marked inhibition of extracellular signal-regulated kinase (ERK) phosphorylation and invasion in PNT1a cells expressing FGFR-1 and FGFR-4 and all prostate cancer cell lines tested. Treatment in vivo completely inhibited VCaP tumor growth and significantly inhibited angiogenesis and proliferation and increased cell death in treated tumors. This was associated with marked inhibition of ERK phosphorylation in treated tumors. Targeting FGFR signaling is a promising new approach to treating aggressive prostate cancer.

Somatostatin Analogues for Receptor Targeted Photodynamic Therapy

PubMed Central

Kaščáková, Slávka; Hofland, Leo J.; De Bruijn, Henriette S.; Ye, Yunpeng; Achilefu, Samuel; van der Wansem, Katy; van der Ploeg-van den Heuvel, Angelique; van Koetsveld, Peter M.; Brugts, Michael P.; van der Lelij, Aart-Jan; Sterenborg, Henricus J. C. M.; ten Hagen, Timo L. M.; Robinson, Dominic J.; van Hagen, Martin P.

2014-01-01

Photodynamic therapy (PDT) is an established treatment modality, used mainly for anticancer therapy that relies on the interaction of photosensitizer, light and oxygen. For the treatment of pathologies in certain anatomical sites, improved targeting of the photosensitizer is necessary to prevent damage to healthy tissue. We report on a novel dual approach of targeted PDT (vascular and cellular targeting) utilizing the expression of neuropeptide somatostatin receptor (sst2) on tumor and neovascular-endothelial cells. We synthesized two conjugates containing the somatostatin analogue [Tyr3]-octreotate and Chlorin e6 (Ce6): Ce6-K3-[Tyr3]-octreotate (1) and Ce6-[Tyr3]-octreotate-K3-[Tyr3]-octreotate (2). Investigation of the uptake and photodynamic activity of conjugates in-vitro in human erythroleukemic K562 cells showed that conjugation of [Tyr3]-octreotate with Ce6 in conjugate 1 enhances uptake (by a factor 2) in cells over-expressing sst2 compared to wild-type cells. Co-treatment with excess free Octreotide abrogated the phototoxicity of conjugate 1 indicative of a specific sst2-mediated effect. In contrast conjugate 2 showed no receptor-mediated effect due to its high hydrophobicity. When compared with un-conjugated Ce6, the PDT activity of conjugate 1 was lower. However, it showed higher photostability which may compensate for its lower phototoxicity. Intra-vital fluorescence pharmacokinetic studies of conjugate 1 in rat skin-fold observation chambers transplanted with sst2 + AR42J acinar pancreas tumors showed significantly different uptake profiles compared to free Ce6. Co-treatment with free Octreotide significantly reduced conjugate uptake in tumor tissue (by a factor 4) as well as in the chamber neo-vasculature. These results show that conjugate 1 might have potential as an in-vivo sst2 targeting photosensitizer conjugate. PMID:25111655

Targeted Radiotherapy of Estrogen Receptor Positive Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raghavan Rajagopalan

The overall objectives of the proposal were to develop estrogen receptor (ER) binding small molecule radiopharmaceuticals for targeted radiotherapy of ER positive (ER+) tumors. In particular, this proposal focused on embedding a {sup 186,188}Re or a {sup 32}P radionuclide into an estrogen steroidal framework by isosteric substitution such that the resulting structure is topologically similar to the estrogen (estrogen mimic). The estrogen mimic molecules expected to bind to the ER and exhibit biodistribution akin to that of native estrogen due to structural mimicry. It is anticipated that the {sup 186,188}Re- or a {sup 32}P-containing estrogen mimics will be useful formore » targeted molecular radiotherapy of ER+ tumors. It is well established that the in vivo target tissue uptake of estrogen like steroidal molecules is related to the binding of the steroids to sex hormone binding globulin (SHBG). SHBG is important in the uptake of estrogens and testosterone in target tissues by SHBG receptors on the cell surface. However, hitherto the design of estrogen like small molecule radiopharmaceuticals was focused on optimizing ER binding characteristics without emphasis on SHBG binding properties. Consequently, even the molecules with good ER affinity in vitro, performed poorly in biodistribution studies. Based on molecular modeling studies the proposal focused on developing estrogen mimics 1-3 which were topologically similar to native estrogens, and form hydrogen bonds in ER and SHBG in the same manner as those of native estrogens. To this end the technical objectives of the proposal focused on synthesizing the rhenium-estrone and estradiol mimics 1 and 2 respectively, and phosphorous estradiol mimic 3 and to assess their stability and in vitro binding characteristics to ER and SHBG.« less

A Plant Immune Receptor Detects Pathogen Effectors that Target WRKY Transcription Factors.

PubMed

Sarris, Panagiotis F; Duxbury, Zane; Huh, Sung Un; Ma, Yan; Segonzac, Cécile; Sklenar, Jan; Derbyshire, Paul; Cevik, Volkan; Rallapalli, Ghanasyam; Saucet, Simon B; Wirthmueller, Lennart; Menke, Frank L H; Sohn, Kee Hoon; Jones, Jonathan D G

2015-05-21

Defense against pathogens in multicellular eukaryotes depends on intracellular immune receptors, yet surveillance by these receptors is poorly understood. Several plant nucleotide-binding, leucine-rich repeat (NB-LRR) immune receptors carry fusions with other protein domains. The Arabidopsis RRS1-R NB-LRR protein carries a C-terminal WRKY DNA binding domain and forms a receptor complex with RPS4, another NB-LRR protein. This complex detects the bacterial effectors AvrRps4 or PopP2 and then activates defense. Both bacterial proteins interact with the RRS1 WRKY domain, and PopP2 acetylates lysines to block DNA binding. PopP2 and AvrRps4 interact with other WRKY domain-containing proteins, suggesting these effectors interfere with WRKY transcription factor-dependent defense, and RPS4/RRS1 has integrated a "decoy" domain that enables detection of effectors that target WRKY proteins. We propose that NB-LRR receptor pairs, one member of which carries an additional protein domain, enable perception of pathogen effectors whose function is to target that domain. Copyright © 2015 Elsevier Inc. All rights reserved.

Potential therapeutic targets for ATP-gated P2X receptor ion channels.

PubMed

Li, Zhiyuan; Liang, Dong; Chen, Ling

2008-04-01

P2X receptors make up a novel family of ligand-gated ion channels that are activated by binding of extracellular ATP. These receptors can form a number of homomeric and heteromeric ion channels, which are widely distributed throughout the human body. They are thought to play an important role in many cellular processes, including synaptic transmission and thrombocyte aggregation. These ion channels are also involved in the pathology of several disease states, including chronic inflammation and neuropathic pain, and thus are the potential targets for drug development. The recent discovery of potent and highly selective antagonists for P2X(7) receptors, through the use of high-throughput screening, has helped to further understand the P2X receptor pharmacology and provided new evidence that P2X(7) receptors play a specific role in chronic pain states. In this review, we discuss how the P2X family of ion channels has distinguished itself as a potential new drug target. We are optimistic that safe and effective candidate drugs will be suitable for progression into clinical development.

Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

PubMed Central

Cook, Katherine L.; Clarke, Pamela A. G.; Parmar, Jignesh; Hu, Rong; Schwartz-Roberts, Jessica L.; Abu-Asab, Mones; Wärri, Anni; Baumann, William T.; Clarke, Robert

2014-01-01

Approximately 70% of all newly diagnosed breast cancers express estrogen receptor (ER)-α. Although inhibiting ER action using targeted therapies such as fulvestrant (ICI) is often effective, later emergence of antiestrogen resistance limits clinical use. We used antiestrogen-sensitive and -resistant cells to determine the effect of antiestrogens/ERα on regulating autophagy and unfolded protein response (UPR) signaling. Knockdown of ERα significantly increased the sensitivity of LCC1 cells (sensitive) and also resensitized LCC9 cells (resistant) to antiestrogen drugs. Interestingly, ERα knockdown, but not ICI, reduced nuclear factor (erythroid-derived 2)-like (NRF)-2 (UPR-induced antioxidant protein) and increased cytosolic kelch-like ECH-associated protein (KEAP)-1 (NRF2 inhibitor), consistent with the observed increase in ROS production. Furthermore, autophagy induction by antiestrogens was prosurvival but did not prevent ERα knockdown–mediated death. We built a novel mathematical model to elucidate the interactions among UPR, autophagy, ER signaling, and ROS regulation of breast cancer cell survival. The experimentally validated mathematical model explains the counterintuitive result that knocking down the main target of ICI (ERα) increased the effectiveness of ICI. Specifically, the model indicated that ERα is no longer present in excess and that the effect on proliferation from further reductions in its level by ICI cannot be compensated for by increased autophagy. The stimulation of signaling that can confer resistance suggests that combining autophagy or UPR inhibitors with antiestrogens would reduce the development of resistance in some breast cancers.—Cook, K. L., Clarke, P. A. G., Parmar, J., Hu, R., Schwartz-Roberts, J. L., Abu-Asab, M., Wärri, A., Baumann, W. T., Clarke, R. Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

Lubiprostone targets prostanoid EP₄ receptors in ovine airways.

PubMed

Cuthbert, A W

2011-01-01

Lubiprostone, a prostaglandin E₁ derivative, is reported to activate ClC-2 chloride channels located in the apical membranes of a number of transporting epithelia. Lack of functioning CFTR chloride channels in epithelia is responsible for the genetic disease cystic fibrosis, therefore, surrogate channels that can operate independently of CFTR are of interest. This study explores the target receptor(s) for lubiprostone in airway epithelium. All experiments were performed on the ventral tracheal epithelium of sheep. Epithelia were used to measure anion secretion from the apical surface as short circuit current or as fluid secretion from individual airway submucosal glands, using an optical method. The EP₄ antagonists L-161982 and GW627368 inhibited short circuit current responses to lubiprostone, while EP₁(,)₂(&)₃ receptor antagonists were without effect. Similarly, lubiprostone induced secretion in airway submucosal glands was inhibited by L-161982. L-161982 effectively competed with lubiprostone with a K(d) value of 0.058 µM, close to its value for binding to human EP₄ receptors (0.024 µM). The selective EP₄ agonist L-902688 and lubiprostone behaved similarly with respect to EP₄ receptor antagonists. Results of experiments with H89, a protein kinase A inhibitor, were consistent with lubiprostone acting through a G(s) -protein coupled EP₄ receptor/cAMP cascade. Lubiprostone-induced short-circuit currents and submucosal gland secretions were inhibited by selective EP₄ receptor antagonists. The results suggest EP₄ receptor activation by lubiprostone triggers cAMP production necessary for CFTR activation and the secretory responses, a possibility precluded in CF tissues. © 2010 The Author. British Journal of Pharmacology © 2010 The British Pharmacological Society.

Diagnostic nanoparticle targeting of the EGF-receptor in complex biological conditions using single-domain antibodies.

PubMed

Zarschler, K; Prapainop, K; Mahon, E; Rocks, L; Bramini, M; Kelly, P M; Stephan, H; Dawson, K A

2014-06-07

For effective localization of functionalized nanoparticles at diseased tissues such as solid tumours or metastases through biorecognition, appropriate targeting vectors directed against selected tumour biomarkers are a key prerequisite. The diversity of such vector molecules ranges from proteins, including antibodies and fragments thereof, through aptamers and glycans to short peptides and small molecules. Here, we analyse the specific nanoparticle targeting capabilities of two previously suggested peptides (D4 and GE11) and a small camelid single-domain antibody (sdAb), representing potential recognition agents for the epidermal growth factor receptor (EGFR). We investigate specificity by way of receptor RNA silencing techniques and look at increasing complexity in vitro by introducing increasing concentrations of human or bovine serum. Peptides D4 and GE11 proved problematic to employ and conjugation resulted in non-receptor specific uptake into cells. Our results show that sdAb-functionalized particles can effectively target the EGFR, even in more complex bovine and human serum conditions where targeting specificity is largely conserved for increasing serum concentration. In human serum however, an inhibition of overall nanoparticle uptake is observed with increasing protein concentration. For highly affine targeting ligands such as sdAbs, targeting a receptor such as EGFR with low serum competitor abundance, receptor recognition function can still be partially realised in complex conditions. Here, we stress the value of evaluating the targeting efficiency of nanoparticle constructs in realistic biological milieu, prior to more extensive in vivo studies.

Cannabinoid Receptors: A Novel Target for Therapy of Prostate Cancer

DTIC Science & Technology

2005-02-01

cannabi - 25. Lee C, Sutkowski DM, Sensibar JA, et al. Regulation activation of the CB(2) cannabinoid receptor. Cancer noids. Nature 1993;365:61-5. of...q0 AD Award Number: W81XWH-04-1-0217 TITLE: Cannabinoid Receptors: A Novel Target for Therapy of Prostate Cancer PRINCIPAL INVESTIGATOR: Hasan...2005 TYPE OF REPORT: Annual 20060215 099 PREPARED FOR: U.S. Army Medical Research and Materiel Command Fort Detrick, Maryland 21702-5012 DISTRIBUTION

Elevated extracellular [K+] inhibits death-receptor- and chemical-mediated apoptosis prior to caspase activation and cytochrome c release.

PubMed Central

Thompson, G J; Langlais, C; Cain, K; Conley, E C; Cohen, G M

2001-01-01

Efflux of intracellular K(+) and cell shrinkage are features of apoptosis in many experimental systems, and a regulatory role has been proposed for cytoplasmic [K(+)] in initiating apoptosis. We have investigated this in both death-receptor-mediated and chemical-induced apoptosis. Using Jurkat T cells pre-loaded with the K(+) ion surrogate (86)Rb(+), we have demonstrated an efflux of intracellular K(+) during apoptosis that was concomitant with, but did not precede, other apoptotic changes, including phosphatidylserine externalization, mitochondrial depolarization and cell shrinkage. To further clarify the role of K(+) ions in apoptosis, cytoprotection by elevated extracellular [K(+)] was studied. Induction of apoptosis by diverse death-receptor and chemical stimuli in two cell lines was inhibited prior to phosphatidylserine externalization, mitochondrial depolarization, cytochrome c release and caspase activation. Using a cell-free system, we have demonstrated a novel mechanism by which increasing [K(+)] inhibited caspase activation. In control dATP-activated lysates, Apaf-1 oligomerized to a biologically active caspase processing approximately 700 kDa complex and an inactive approximately 1.4 MDa complex. Increasing [K(+)] inhibited caspase activation by preventing formation of the approximately 700 kDa complex, but not of the inactive complex. Thus intracellular and extracellular [K(+)] markedly affect caspase activation and the initiation of apoptosis induced by both death-receptor ligation and chemical stress. PMID:11415444

Folate targeted polymeric 'green' nanotherapy for cancer

NASA Astrophysics Data System (ADS)

Narayanan, Sreeja; Binulal, N. S.; Mony, Ullas; Manzoor, Koyakutty; Nair, Shantikumar; Menon, Deepthy

2010-07-01

The concept of 'green' chemotherapy by employing targeted nanoparticle mediated delivery to enhance the efficacy of phytomedicines is reported. Poly (lactide-co-glycolide) (PLGA) nanoparticles encapsulating a well known nutraceutical namely, grape seed extract (GSE)—'NanoGSE'—was prepared by a nanoprecipitation technique. The drug-loaded nanoparticles of size ~ 100 nm exhibited high colloidal stability at physiological pH. Molecular receptor targeting of this nanophytomedicine against folate receptor over-expressing cancers was demonstrated in vitro by conjugation with a potential cancer targeting ligand, folic acid (FA). Fluorescence microscopy and flow cytometry data showed highly specific cellular uptake of FA conjugated NanoGSE on folate receptor positive cancer cells. Studies were also conducted to investigate the efficiency of targeted (FA conjugated) versus non-targeted (non-FA conjugated) nanoformulations in causing cancer cell death. The IC50 values were lowered by a factor of ~ 3 for FA-NanoGSE compared to the free drug, indicating substantially enhanced bioavailability to the tumor cells, sparing the normal ones. Receptor targeting of FA-NanoGSE resulted in a significant increase in apoptotic index, which was also quantified by flow cytometry and fluorescence microscopy. This in vitro study provides a basis for the use of nanoparticle mediated delivery of anticancer nutraceuticals to enhance bioavailability and effectively target cancer by a 'green' approach.

Targeting Androgen Receptor Aberrations in Castration-Resistant Prostate Cancer.

PubMed

Sharp, Adam; Welti, Jonathan; Blagg, Julian; de Bono, Johann S

2016-09-01

Androgen receptor (AR) splice variants (SV) have been implicated in the development of metastatic castration-resistant prostate cancer and resistance to AR targeting therapies, including abiraterone and enzalutamide. Agents targeting AR-SV are urgently needed to test this hypothesis and further improve the outcome of patients suffering from this lethal disease. Clin Cancer Res; 22(17); 4280-2. ©2016 AACRSee related article by Yang et al., p. 4466. ©2016 American Association for Cancer Research.

Angiotensin II potentiates zinc-induced cortical neuronal death by acting on angiotensin II type 2 receptor.

PubMed

Park, Mi-Ha; Kim, Ha Na; Lim, Joon Seo; Ahn, Jae-Sung; Koh, Jae-Young

2013-12-01

The angiotensin system has several non-vascular functions in the central nervous system. For instance, inhibition of the brain angiotensin system results in a reduction in neuronal death following acute brain injury such as ischemia and intracerebral hemorrhage, even under conditions of constant blood pressure. Since endogenous zinc has been implicated as a key mediator of ischemic neuronal death, we investigated the possibility that the angiotensin system affects the outcome of zinc-triggered neuronal death in cortical cell cultures. Exposure of cortical cultures containing neurons and astrocytes to 300 μM zinc for 15 min induced submaximal death in both types of cells. Interestingly, addition of angiotensin II significantly enhanced the zinc-triggered neuronal death, while leaving astrocytic cell death relatively unchanged. Both type 1 and 2 angiotensin II receptors (AT1R and AT2R, respectively) were expressed in neurons as well as astrocytes. Zinc neurotoxicity was substantially attenuated by PD123319, a specific inhibitor of AT2R, and augmented by CGP42112, a selective activator of AT2R, indicating a critical role for this receptor subtype in the augmentation of neuronal cell death.Because zinc toxicity occurs largely through oxidative stress, the levels of superoxides in zinc-treated neurons were assessed by DCF fluorescence microscopy. Combined treatment with zinc and angiotensin II substantially increased the levels of superoxides in neurons compared to those induced by zinc alone. This increase in oxidative stress by angiotensin II was completely blocked by the addition of PD123319. Finally, since zinc-induced oxidative stress may be caused by induction and/or activation of NADPH oxidase, the activation status of Rac and the level of the NADPH oxidase subunit p67phox were measured. Angiotensin II markedly increased Rac activity and the levels of p67phox in zinc-treated neurons and astrocytes in a PD123319-dependent manner. The present study shows that the

FAS Death Receptor: A Breast Cancer Subtype-Specific Radiation Response Biomarker and Potential Therapeutic Target

PubMed Central

Horton, Janet K.; Siamakpour-Reihani, Sharareh; Lee, Chen-Ting; Zhou, Ying; Chen, Wei; Geradts, Joseph; Fels, Diane R.; Hoang, Peter; Ashcraft, Kathleen A.; Groth, Jeff; Kung, Hsiu-Ni; Dewhirst, Mark W.; Chi, Jen-Tsan A.

2015-01-01

Although a standardized approach to radiotherapy has been used to treat breast cancer, regardless of subtype (e.g., luminal, basal), recent clinical data suggest that radiation response may vary significantly among subtypes. We hypothesized that this clinical variability may be due, in part, to differences in cellular radiation response. In this study, we utilized RNA samples for microarray analysis from two sources: 1. Paired pre- and postirradiation breast tumor tissue from 32 early-stage breast cancer patients treated in our unique preoperative radiation Phase I trial; and 2. Sixteen biologically diverse breast tumor cell lines exposed to 0 and 5 Gy irradiation. The transcriptome response to radiation exposure was derived by comparing gene expression in samples before and after irradiation. Genes with the highest coefficient of variation were selected for further evaluation and validated at the RNA and protein level. Gene editing and agonistic antibody treatment were performed to assess the impact of gene modulation on radiation response. Gene expression in our cohort of luminal breast cancer patients was distinctly different before and after irradiation. Further, two distinct patterns of gene expression were observed in our biologically diverse group of breast cancer cell lines pre- versus postirradiation. Cell lines that showed significant change after irradiation were largely luminal subtype, while gene expression in the basal and HER2+ cell lines was minimally impacted. The 100 genes with the most significant response to radiation in patients were identified and analyzed for differential patterns of expression in the radiation-responsive versus nonresponsive cell lines. Fourteen genes were identified as significant, including FAS, a member of the tumor necrosis factor receptor family known to play a critical role in programed cell death. Modulation of FAS in breast cancer cell lines altered radiation response phenotype and enhanced radiation sensitivity in

Targeting the dopamine D3 receptor: an overview of drug design strategies.

PubMed

Cortés, Antoni; Moreno, Estefanía; Rodríguez-Ruiz, Mar; Canela, Enric I; Casadó, Vicent

2016-07-01

Dopamine is a neurotransmitter widely distributed in both the periphery and the central nervous system (CNS). Its physiological effects are mediated by five closely related G protein-coupled receptors (GPCRs) that are divided into two major subclasses: the D1-like (D1, D5) and the D2-like (D2, D3, D4) receptors. D3 receptors (D3Rs) have the highest density in the limbic areas of the brain, which are associated with cognitive and emotional functions. These receptors are therefore attractive targets for therapeutic management. This review summarizes the functional and pharmacological characteristics of D3Rs, including the design and clinical relevance of full agonists, partial agonists and antagonists, as well as the capacity of these receptors to form active homodimers, heterodimers or higher order receptor complexes as pharmacological targets in several neurological and neurodegenerative disorders. The high sequence homology between D3R and the D2-type challenges the development of D3R-selective compounds. The design of new D3R-preferential ligands with improved physicochemical properties should provide a better pharmacokinetic/bioavailability profile and lesser toxicity than is found with existing D3R ligands. It is also essential to optimize D3R affinity and, especially, D3R vs. D2-type binding and functional selectivity ratios. Developing allosteric and bitopic ligands should help to improve the D3R selectivity of these drugs. As most evidence points to the ability of GPCRs to form homomers and heteromers, the most promising therapeutic strategy in the future is likely to involve the application of heteromer-selective drugs. These selective ligands would display different affinities for a given receptor depending on the receptor partners within the heteromer. Therefore, designing novel compounds that specifically target and modulate D1R-D3R heteromers would be an interesting approach for the treatment of levodopa (L-DOPA)-induced dyskinesias.

Endothelial microparticle uptake in target cells is annexin I/phosphatidylserine receptor dependent and prevents apoptosis.

PubMed

Jansen, Felix; Yang, Xiaoyan; Hoyer, Friedrich Felix; Paul, Kathrin; Heiermann, Nadine; Becher, Marc Ulrich; Abu Hussein, Nebal; Kebschull, Moritz; Bedorf, Jörg; Franklin, Bernardo S; Latz, Eicke; Nickenig, Georg; Werner, Nikos

2012-08-01

Endothelial microparticles (EMP) are released from activated or apoptotic cells, but their effect on target cells and the exact way of incorporation are largely unknown. We sought to determine the uptake mechanism and the biological effect of EMP on endothelial and endothelial-regenerating cells. EMP were generated from starved endothelial cells and isolated by ultracentrifugation. Caspase 3 activity assay and terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that EMP protect target endothelial cells against apoptosis in a dose-dependent manner. Proteomic analysis was performed to identify molecules contained in EMP, which might be involved in EMP uptake. Expression of annexin I in EMP was found and confirmed by Western blot, whereas the corresponding receptor phosphatidylserine receptor was present on endothelial target cells. Silencing either annexin I on EMP or phosphatidylserine receptor on target cells using small interfering RNA showed that the uptake of EMP by human coronary artery endothelial cells is annexin I/phosphatidylserine receptor dependent. Annexin I-downregulated EMP abrogated the EMP-mediated protection against apoptosis of endothelial target cells. p38 activation was found to mediate camptothecin-induced apoptosis. Finally, human coronary artery endothelial cells pretreated with EMP inhibited camptothecin-induced p38 activation. EMP are incorporated by endothelial cells in an annexin I/phosphatidylserine receptor-dependent manner and protect target cells against apoptosis. Inhibition of p38 activity is involved in EMP-mediated protection against apoptosis.

Absence of Toll-like receptor 4 signaling results in delayed Yersinia enterocolitica YopP-induced cell death of dendritic cells.

PubMed

Gröbner, Sabine; Schulz, Sebastian; Soldanova, Irena; Gunst, Dani S J; Waibel, Michaela; Wesselborg, Sebastian; Borgmann, Stefan; Autenrieth, Ingo B

2007-01-01

In an initial period (< or =4 h) Toll-like receptor 4 (TLR4) signaling is required for Yersinia enterocolitica YopP-induced dendritic cell (DC) death. Later (>4 h), DC die independent of TLR4 signaling. In TLR4-deficient DC caspase 8 cleavage is delayed, indicating that TLR4 signaling accelerates caspase 8 activation, leading to DC death.

The Fas/CD95 Receptor Regulates the Death of Autoreactive B Cells and the Selection of Antigen-Specific B Cells

PubMed Central

Koncz, Gabor; Hueber, Anne-Odile

2012-01-01

Cell death receptors have crucial roles in the regulation of immune responses. Here we review recent in vivo data confirming that the Fas death receptor (TNFSR6) on B cells is important for the regulation of autoimmunity since the impairment of only Fas function on B cells results in uncontrolled autoantibody production and autoimmunity. Fas plays a role in the elimination of the non-specific and autoreactive B cells in germinal center, while during the selection of antigen-specific B cells different escape signals ensure the resistance to Fas-mediated apoptosis. Antigen-specific survival such as BCR or MHCII signal or coreceptors (CD19) cooperating with BCR inhibits the formation of death inducing signaling complex. Antigen-specific survival can be reinforced by antigen-independent signals of IL-4 or CD40 overproducing the anti-apoptotic members of the Bcl-2 family proteins. PMID:22848207

TRAIL Death Receptor-4 Expression Positively Correlates With the Tumor Grade in Breast Cancer Patients With Invasive Ductal Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanlioglu, Ahter D.; Department of Medical Biology and Genetics, Akdeniz University Faculty of Medicine, Antalya; Korcum, Aylin F.

2007-11-01

Purpose: Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in cancer cells but not in normal cells, and a number of clinical trials have recently been initiated to test the safety and antitumoral potential of TRAIL in cancer patients. Four different receptors have been identified to interact with TRAIL: two are death-inducing receptors (TRAIL-R1 [DR4] and TRAIL-R2 [DR5]), whereas the other two (TRAIL-R3 [DcR1] and TRAIL-R4 [DcR2]) do not induce death upon ligation and are believed to counteract TRAIL-induced cytotoxicity. Because high levels of DcR2 expression have recently been correlated with carcinogenesis in the prostate and lung, thismore » study investigated the importance of TRAIL and TRAIL receptor expression in breast cancer patients with invasive ductal carcinoma, taking various prognostic markers into consideration. Methods and Materials: Immunohistochemical analyses were performed on 90 breast cancer patients with invasive ductal carcinoma using TRAIL and TRAIL receptor-specific antibodies. Age, menopausal status, tumor size, lymph node status, tumor grade, lymphovascular invasion, perineural invasion, extracapsular tumor extension, presence of an extensive intraductal component, multicentricity, estrogen and progesterone receptor status, and CerbB2 expression levels were analyzed with respect to TRAIL/TRAIL receptor expression patterns. Results: The highest TRAIL receptor expressed in patients with invasive ductal carcinoma was DR4. Although progesterone receptor-positive patients exhibited lower DR5 expression, CerbB2-positive tissues displayed higher levels of both DR5 and TRAIL expressions. Conclusions: DR4 expression positively correlates with the tumor grade in breast cancer patients with invasive ductal carcinoma.« less

Sigma-1 receptor: the novel intracellular target of neuropsychotherapeutic drugs.

PubMed

Hayashi, Teruo

2015-01-01

Sigma-1 receptor ligands have been long expected to serve as drugs for treatment of human diseases such as neurodegenerative disorders, depression, idiopathic pain, drug abuse, and cancer. Recent research exploring the molecular function of the sigma-1 receptor started unveiling underlying mechanisms of the therapeutic activity of those ligands. Via the molecular chaperone activity, the sigma-1 receptor regulates protein folding/degradation, ER/oxidative stress, and cell survival. The chaperone activity is activated or inhibited by synthetic sigma-1 receptor ligands in an agonist-antagonist manner. Sigma-1 receptors are localized at the endoplasmic reticulum (ER) membranes that are physically associated with the mitochondria (MAM: mitochondria-associated ER membrane). In specific types of neurons (e.g., those at the spinal cord), sigma-1 receptors are also clustered at ER membranes that juxtapose postsynaptic plasma membranes. Recent studies indicate that sigma-1 receptors, partly in sake of its unique subcellular localization, regulate the mitochondria function that involves bioenergetics and free radical generation. The sigma-1 receptor may thus provide an intracellular drug target that enables controlling ER stress and free radical generation under pathological conditions. Copyright © 2014 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.

Multicolor fluorescence "click"-chemistry as a means to select membrane targets for pre-targeting approaches by function of their receptor kinetics.

PubMed

van der Wal, Steffen; de Korne, Clarize M; Sand, Laurens L G; van Willigen, Danny M; Hogendoorn, Pancras C W; Szuhai, Karoly; van Leeuwen, Fijs W B; Buckle, Tessa

2018-06-04

Availability of a receptor for theranostic pre-targeting approaches was assessed using a novel "click" chemistry-based de-activatable fluorescence-quenching concept. Efficacy was evaluated in a cell-based model system that exhibits both membranous (available) and internalized (unavailable) receptor-fractions of the clinically relevant receptor chemokine receptor 4 (CXCR4). Proof of concept was based on a de-activatable tracer consisting out of a CXCR4 specific peptide functionalized with a Cy5 dye comprising a chemo-selective azide handle (N3-Cy5-AcTZ14011). Reaction with a Cy7 quencher dye (Cy7-DBCO) resulted in optically silent Cy7-["click"]-Cy5-AcTZ14011. In situ a >90% FRET-based reduction of signal intensity of N3-Cy5-AcTZ14011 (KD 222.4 ± 25.2 nM) was seen within minutes after quencher addition. In cells, discrimination between the membranous and internalized receptor-fraction could be made through quantitative assessment of quenching/internalization kinetics. As such, using this approach screening of membrane receptors and their applicability in receptor-(pre-)targeted theranostics can become straightforward. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lipid-sensors, enigmatic-orphan and orphan nuclear receptors as therapeutic targets in breast-cancer.

PubMed

Garattini, Enrico; Bolis, Marco; Gianni', Maurizio; Paroni, Gabriela; Fratelli, Maddalena; Terao, Mineko

2016-07-05

Breast-cancer is heterogeneous and consists of various groups with different biological characteristics. Innovative pharmacological approaches accounting for this heterogeneity are needed. The forty eight human Nuclear-Hormone-Receptors are ligand-dependent transcription-factors and are classified into Endocrine-Receptors, Adopted-Orphan-Receptors (Lipid-sensors and Enigmatic-Orphans) and Orphan-receptors. Nuclear-Receptors represent ideal targets for the design/synthesis of pharmacological ligands. We provide an overview of the literature available on the expression and potential role played by Lipid-sensors, Enigmatic-Orphans and Orphan-Receptors in breast-cancer. The data are complemented by an analysis of the expression levels of each selected Nuclear-Receptor in the PAM50 breast-cancer groups, following re-elaboration of the data publicly available. The major aim is to support the idea that some of the Nuclear-Receptors represent largely unexploited therapeutic-targets in breast-cancer treatment/chemo-prevention. On the basis of our analysis, we conclude that the Lipid-Sensors, NR1C3, NR1H2 and NR1H3 are likely to be onco-suppressors in breast-cancer. The Enigmatic-Orphans, NR1F1 NR2A1 and NR3B3 as well as the Orphan-Receptors, NR0B1, NR0B2, NR1D1, NR2F1, NR2F2 and NR4A3 exert a similar action. These Nuclear-Receptors represent candidates for the development of therapeutic strategies aimed at increasing their expression or activating them in tumor cells. The group of Nuclear-Receptors endowed with potential oncogenic properties consists of the Lipid-Sensors, NR1C2 and NR1I2, the Enigmatic-Orphans, NR1F3, NR3B1 and NR5A2, as well as the Orphan-Receptors, NR2E1, NR2E3 and NR6A1. These oncogenic Nuclear-Receptors should be targeted with selective antagonists, reverse-agonists or agents/strategies capable of reducing their expression in breast-cancer cells.

Design and evaluation of dual CD44 receptor and folate receptor-targeting double-smart pH-response multifunctional nanocarrier

NASA Astrophysics Data System (ADS)

Chen, Daquan; Song, Xiaoyan; Wang, Kaili; Guo, Chunjing; Yu, Yueming; Fan, Huaying; Zhao, Feng

2017-12-01

In this article, in order to enhance the bioavailiability and tumor targeting of curcumin (Cur), the oligosaccharides of hyaluronan conjugates, folic acid-oligosaccharides of hyaluronan-acetal-menthone 1,2-glycerol ketal (FA-oHA-Ace-MGK) carried oHA as a ligand to CD44 receptor, double-pH-sensitive Ace-MGK as hydrophobic moieties, and FA as the target of folate receptor. The structure characteristics of this smart response multifunctional dual-targeting nano-sized carrier was measured by fourier-transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR). Cur, an anticancer drug, was successfully loaded in FA-oHA-Ace-MGK micelles by self-assembly. The measurement results of transmission electron microscopy (TEM) presented that the Cur-loaded micelles were spherical in shape with the average size of 166.3 ± 2.12 nm and zeta potential - 30.07 mV. Much more encapsulated Cur could be released at mildly acidic environments than at pH 7.4, from the Cur-FA-oHA-Ace-MGK micelles. Cytotoxicity assay indicated that non-Cur loaded micelles mostly had no cytotoxicity to MCF-7 cells and A549 cells, and Cur-loaded micelles had significantly lower survival rate than Cur suspension in the same concentration, which proved that the drug-loaded micelles can effectively inhibit tumor cell growth. The targeting of CD44 receptors and folate receptors was proved in vitro cellular uptake assay. These results showed the promising potential of FA-oHA-Ace-MGK as an effective nano-sized carrier for anti-tumor drug delivery.

Targeting multiple opioid receptors - improved analgesics with reduced side effects?

PubMed

Günther, Thomas; Dasgupta, Pooja; Mann, Anika; Miess, Elke; Kliewer, Andrea; Fritzwanker, Sebastian; Steinborn, Ralph; Schulz, Stefan

2017-04-05

Classical opioid analgesics, including morphine, mediate all of their desired and undesired effects by specific activation of the μ-opioid receptor (μ receptor). The use of morphine for treating chronic pain, however, is limited by the development of constipation, respiratory depression, tolerance and dependence. Analgesic effects can also be mediated through other members of the opioid receptor family such as the κ-opioid receptor (κ receptor), δ-opioid receptor (δ receptor) and the nociceptin/orphanin FQ peptide receptor (NOP receptor). Currently, a new generation of opioid analgesics is being developed that can simultaneously bind with high affinity to multiple opioid receptors. With this new action profile, it is hoped that additional analgesic effects and fewer side effects can be achieved. Recent research is mainly focused on the development of bifunctional μ/NOP receptor agonists, which has already led to novel lead structures such as the spiroindole-based cebranopadol and a compound class with a piperidin-4-yl-1,3-dihydroindol-2-one backbone (SR16835/AT-202 and SR14150/AT-200). In addition, the ornivol BU08028 is an analogue of the clinically well-established buprenorphine. Moreover, the morphinan-based nalfurafine exerts its effect with a dominant κ receptor-component and is therefore utilized in the treatment of pruritus. The very potent dihydroetorphine is a true multi-receptor opioid ligand in that it binds to μ, κ and δ receptors. The main focus of this review is to assess the paradigm of opioid ligands targeting multiple receptors with a single chemical entity. We reflect on this rationale by discussing the biological actions of particular multi-opioid receptor ligands, but not on their medicinal chemistry and design. © 2017 The British Pharmacological Society.

Identification of the Calmodulin-Binding Domains of Fas Death Receptor

PubMed Central

Chang, Bliss J.; Samal, Alexandra B.; Vlach, Jiri; Fernandez, Timothy F.; Brooke, Dewey; Prevelige, Peter E.; Saad, Jamil S.

2016-01-01

The extrinsic apoptotic pathway is initiated by binding of a Fas ligand to the ectodomain of the surface death receptor Fas protein. Subsequently, the intracellular death domain of Fas (FasDD) and that of the Fas-associated protein (FADD) interact to form the core of the death-inducing signaling complex (DISC), a crucial step for activation of caspases that induce cell death. Previous studies have shown that calmodulin (CaM) is recruited into the DISC in cholangiocarcinoma cells and specifically interacts with FasDD to regulate the apoptotic/survival signaling pathway. Inhibition of CaM activity in DISC stimulates apoptosis significantly. We have recently shown that CaM forms a ternary complex with FasDD (2:1 CaM:FasDD). However, the molecular mechanism by which CaM binds to two distinct FasDD motifs is not fully understood. Here, we employed mass spectrometry, nuclear magnetic resonance (NMR), biophysical, and biochemical methods to identify the binding regions of FasDD and provide a molecular basis for the role of CaM in Fas–mediated apoptosis. Proteolytic digestion and mass spectrometry data revealed that peptides spanning residues 209–239 (Fas-Pep1) and 251–288 (Fas-Pep2) constitute the two CaM-binding regions of FasDD. To determine the molecular mechanism of interaction, we have characterized the binding of recombinant/synthetic Fas-Pep1 and Fas-Pep2 peptides with CaM. Our data show that both peptides engage the N- and C-terminal lobes of CaM simultaneously. Binding of Fas-Pep1 to CaM is entropically driven while that of Fas-Pep2 to CaM is enthalpically driven, indicating that a combination of electrostatic and hydrophobic forces contribute to the stabilization of the FasDD–CaM complex. Our data suggest that because Fas-Pep1 and Fas-Pep2 are involved in extensive intermolecular contacts with the death domain of FADD, binding of CaM to these regions may hinder its ability to bind to FADD, thus greatly inhibiting the initiation of apoptotic signaling

Identification of Molecular Receptors for Therapeutic Targeting in Prostate Cancer

DTIC Science & Technology

2006-12-01

prostate cancer: potential role of androgen and ErbB receptor signal transduction crosstalk. Neoplasia. 5, 99-109 (2003). 10. Kolonin, M., Pasqualini , R...and Arap, W. Molecular addresses in blood vessels as targets for therapy. Curr. Opin. Chem. Biol. 5, 308-313 (2001). 11. Pasqualini , R., and...Ruoslahti, E. Organ targeting in vivo using phage display peptide libraries. Nature 380, 364-366 (1996). 12. Arap, W., Pasqualini , R., and Ruoslahti, E

Peroxisome proliferator-activated receptors (PPARs) as therapeutic target in neurodegenerative disorders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarwal, Swati; Yadav, Anuradha; Academy of Scientific and Innovative Research

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors and they serve to be a promising therapeutic target for several neurodegenerative disorders, which includes Parkinson disease, Alzheimer's disease, Huntington disease and Amyotrophic Lateral Sclerosis. PPARs play an important role in the downregulation of mitochondrial dysfunction, proteasomal dysfunction, oxidative stress, and neuroinflammation, which are the major causes of the pathogenesis of neurodegenerative disorders. In this review, we discuss about the role of PPARs as therapeutic targets in neurodegenerative disorders. Several experimental approaches suggest potential application of PPAR agonist as well as antagonist in the treatment of neurodegenerative disorders. Several epidemiological studies found thatmore » the regular usage of PPAR activating non-steroidal anti-inflammatory drugs is effective in decreasing the progression of neurodegenerative diseases including PD and AD. We also reviewed the neuroprotective effects of PPAR agonists and associated mechanism of action in several neurodegenerative disorders both in vitro as well as in vivo animal models. - Highlights: • Peroxisome -activated receptors (PPARs) serve to be a promising therapeutic target for several neurodegenerative disorders. • PPAR agonist as well as provides neuroprotection in vitro as well as in vivo animal models of neurodegenerative disorders. • PPAR activating anti-inflammatory drugs use is effective in decreasing progression of neurodegenerative diseases.« less

Near infrared spectral polarization imaging of prostate cancer tissues using Cybesin: a receptor-targeted contrast agent

NASA Astrophysics Data System (ADS)

Pu, Yang; Wang, W. B.; Tang, G. C.; Liang, Kexian; Achilefu, S.; Alfano, R. R.

2013-03-01

Cybesin, a smart contrast agent to target cancer cells, was investigated using a near infrared (NIR) spectral polarization imaging technique for prostate cancer detection. The approach relies on applying a contrast agent that can target cancer cells. Cybesin, as a small ICG-derivative dye-peptide, emit fluorescence between 750 nm and 900 nm, which is in the "tissue optical window". Cybesin was reported targeting the over-expressed bombesin receptors in cancer cells in animal model and the human prostate cancers over-expressing bombesin receptors. The NIR spectral polarization imaging study reported here demonstrated that Cybesin can be used as a smart optical biomarker and as a prostate cancer receptor targeted contrast agent.

Cell Death Pathways in Mutant Rhodopsin Rat Models Identifies Genotype-Specific Targets Controlling Retinal Degeneration.

PubMed

Viringipurampeer, Ishaq A; Gregory-Evans, Cheryl Y; Metcalfe, Andrew L; Bashar, Emran; Moritz, Orson L; Gregory-Evans, Kevin

2018-06-18

Retinitis pigmentosa (RP) is a group of inherited neurological disorders characterized by rod photoreceptor cell death, followed by secondary cone cell death leading to progressive blindness. Currently, there are no viable treatment options for RP. Due to incomplete knowledge of the molecular signaling pathways associated with RP pathogenesis, designing therapeutic strategies remains a challenge. In particular, preventing secondary cone photoreceptor cell loss is a key goal in designing potential therapies. In this study, we identified the main drivers of rod cell death and secondary cone loss in the transgenic S334ter rhodopsin rat model, tested the efficacy of specific cell death inhibitors on retinal function, and compared the effect of combining drugs to target multiple pathways in the S334ter and P23H rhodopsin rat models. The primary driver of early rod cell death in the S334ter model was a caspase-dependent process, whereas cone cell death occurred though RIP3-dependent necroptosis. In comparison, rod cell death in the P23H model was via necroptotic signaling, whereas cone cell loss occurred through inflammasome activation. Combination therapy of four drugs worked better than the individual drugs in the P23H model but not in the S334ter model. These differences imply that treatment modalities need to be tailored for each genotype. Taken together, our data demonstrate that rationally designed genotype-specific drug combinations will be an important requisite to effectively target primary rod cell loss and more importantly secondary cone survival.

Nicotinic receptors as CNS targets for Parkinson's disease.

PubMed

Quik, Maryka; Bordia, Tanuja; O'Leary, Kathryn

2007-10-15

Parkinson's disease is a debilitating neurodegenerative movement disorder characterized by damage to the nigrostriatal dopaminergic system. Current therapies are symptomatic only and may be accompanied by serious side effects. There is therefore a continual search for novel compounds for the treatment of Parkinson's disease symptoms, as well as to reduce or halt disease progression. Nicotine administration has been reported to improve motor deficits that arise with nigrostriatal damage in parkinsonian animals and in Parkinson's disease. In addition, nicotine protects against nigrostriatal damage in experimental models, findings that have led to the suggestion that the reduced incidence of Parkinson's disease in smokers may be due to the nicotine in tobacco. Altogether, these observations suggest that nicotine treatment may be beneficial in Parkinson's disease. Nicotine interacts with multiple nicotinic receptor (nAChR) subtypes in the peripheral and central nervous system, as well as in skeletal muscle. Work to identify the subtypes affected in Parkinson's disease is therefore critical for the development of targeted therapies. Results show that striatal alpha6beta2-containing nAChRs are particularly susceptible to nigrostriatal damage, with a decline in receptor levels that closely parallels losses in striatal dopamine. In contrast, alpha4beta2-containing nAChRs are decreased to a much smaller extent under the same conditions. These observations suggest that development of nAChR agonists or antagonists targeted to alpha6beta2-containing nAChRs may represent a particularly relevant target for Parkinson's disease therapeutics.

Angiotensin II attenuates NMDA receptor-mediated neuronal cell death and prevents the associated reduction in Bcl-2 expression.

PubMed

Schelman, William R; Andres, Robert; Ferguson, Paul; Orr, Brent; Kang, Evan; Weyhenmeyer, James A

2004-09-10

While angiotensin II (Ang II) plays a major role in the regulation of blood pressure, fluid homeostasis and neuroendocrine function, recent studies have also implicated the peptide hormone in cell growth, differentiation and apoptosis. In support of this, we have previously demonstrated that Ang II attenuates N-methyl-D-aspartate (NMDA) receptor signaling [Molec. Brain Res. 48 (1997) 197]. To further examine the modulatory role of Ang II on NMDA receptor function, we investigated the effect of angiotensin receptor (AT) activation on NMDA-mediated cell death and the accompanying decrease in Bcl-2 expression. The viability of differentiated N1E-115 and NG108-15 neuronal cell lines was reduced following exposure to NMDA in a dose-dependent manner. MTT analysis (mitochondrial integrity) revealed a decrease in cell survival of 49.4+/-12.3% in NG108 cells and 79.9+/-6.8% in N1E cells following treatment with 10 mM NMDA for 20 h. Cytotoxicity in N1E cells was inhibited by the noncompetitive NMDA receptor antagonist, MK-801. Further, NMDA receptor-mediated cell death in NG108 cells was attenuated by treatment with Ang II. The Ang II effect was inhibited by both AT1 and AT2 receptor antagonists, losartan and PD123319, respectively, suggesting that both receptor subtypes may play a role in the survival effect of Ang II. Since it has been shown that activation of NMDA receptors alters the expression of Bcl-2 family proteins, Western blot analysis was performed in N1E cells to determine whether Ang II alters the NMDA-induced changes in Bcl-2 expression. A concentration-dependent decrease of intracellular Bcl-2 protein levels was observed following treatment with NMDA, and this reduction was inhibited by MK801. Addition of Ang II suppressed the NMDA receptor-mediated reduction in Bcl-2. The Ang II effect on NMDA-mediated changes in Bcl-2 levels was blocked by PD123319, but was not significantly changed by losartan, suggesting AT2 receptor specificity. Taken together, these

Novel GABA receptor pesticide targets.

PubMed

Casida, John E; Durkin, Kathleen A

2015-06-01

The γ-aminobutyric acid (GABA) receptor has four distinct but overlapping and coupled targets of pesticide action importantly associated with little or no cross-resistance. The target sites are differentiated by binding assays with specific radioligands, resistant strains, site-directed mutagenesis and molecular modeling. Three of the targets are for non-competitive antagonists (NCAs) or channel blockers of widely varied chemotypes. The target of the first generation (20th century) NCAs differs between the larger or elongated compounds (NCA-IA) including many important insecticides of the past (cyclodienes and polychlorocycloalkanes) or present (fiproles) and the smaller or compact compounds (NCA-IB) highly toxic to mammals and known as cage convulsants, rodenticides or chemical threat agents. The target of greatest current interest is designated NCA-II for the second generation (21st century) of NCAs consisting for now of isoxazolines and meta-diamides. This new and uniquely different NCA-II site apparently differs enough between insects and mammals to confer selective toxicity. The fourth target is the avermectin site (AVE) for allosteric modulators of the chloride channel. NCA pesticides vary in molecular surface area and solvent accessible volume relative to avermectin with NCA-IBs at 20-22%, NCA-IAs at 40-45% and NCA-IIs at 57-60%. The same type of relationship relative to ligand-docked length is 27-43% for NCA-IBs, 63-71% for NCA-IAs and 85-105% for NCA-IIs. The four targets are compared by molecular modeling for the Drosophila melanogaster GABA-R. The principal sites of interaction are proposed to be: pore V1' and A2' for NCA-IB compounds; pore A2', L6' and T9' for NCA-IA compounds; pore T9' to S15' in proximity to M1/M3 subunit interface (or alternatively an interstitial site) for NCA-II compounds; and M1/M3, M2 interfaces for AVE. Understanding the relationships of these four binding sites is important in resistance management and in the discovery and use

Active radar guides missile to its target: receptor-based targeted treatment of hepatocellular carcinoma by nanoparticulate systems.

PubMed

Yan, Jing-Jun; Liao, Jia-Zhi; Lin, Ju-Sheng; He, Xing-Xing

2015-01-01

Patients with hepatocellular carcinoma (HCC) usually present at advanced stages and do not benefit from surgical resection, so drug therapy should deserve a prominent place in unresectable HCC treatment. But chemotherapy agents, such as doxorubicin, cisplatin, and paclitaxel, frequently encounter important problems such as low specificity and non-selective biodistribution. Recently, the development of nanotechnology led to significant breakthroughs to overcome these problems. Decorating the surfaces of nanoparticulate-based drug carriers with homing devices has demonstrated its potential in concentrating chemotherapy agents specifically to HCC cells. In this paper, we reviewed the current status of active targeting strategies for nanoparticulate systems based on various receptors such as asialoglycoprotein receptor, transferrin receptor, epidermal growth factor receptor, folate receptor, integrin, and CD44, which are abundantly expressed on the surfaces of hepatocytes or liver cancer cells. Furthermore, we pointed out their merits and defects and provided theoretical references for further research.

Yersinia pestis targets neutrophils via complement receptor 3

PubMed Central

Merritt, Peter M.; Nero, Thomas; Bohman, Lesley; Felek, Suleyman; Krukonis, Eric S.; Marketon, Melanie M.

2015-01-01

Yersinia species display a tropism for lymphoid tissues during infection, and the bacteria select innate immune cells for delivery of cytotoxic effectors by the type III secretion system. Yet the mechanism for target cell selection remains a mystery. Here we investigate the interaction of Yersinia pestis with murine splenocytes to identify factors that participate in the targeting process. We find that interactions with primary immune cells rely on multiple factors. First, the bacterial adhesin Ail is required for efficient targeting of neutrophils in vivo. However, Ail does not appear to directly mediate binding to a specific cell type. Instead, we find that host serum factors direct Y. pestis to specific innate immune cells, particularly neutrophils. Importantly, specificity towards neutrophils was increased in the absence of bacterial adhesins due to reduced targeting of other cell types, but this phenotype was only visible in the presence of mouse serum. Addition of antibodies against complement receptor 3 and CD14 blocked target cell selection, suggesting that a combination of host factors participate in steering bacteria toward neutrophils during plague infection. PMID:25359083

FasL-triggered death of Jurkat cells requires caspase 8-induced, ATP-dependent cross-talk between Fas and the purinergic receptor P2X(7).

PubMed

Aguirre, Adam; Shoji, Kenji F; Sáez, Juan C; Henríquez, Mauricio; Quest, Andrew F G

2013-02-01

Fas ligation via the ligand FasL activates the caspase-8/caspase-3-dependent extrinsic death pathway. In so-called type II cells, an additional mechanism involving tBid-mediated caspase-9 activation is required to efficiently trigger cell death. Other pathways linking FasL-Fas interaction to activation of the intrinsic cell death pathway remain unknown. However, ATP release and subsequent activation of purinergic P2X(7) receptors (P2X(7)Rs) favors cell death in some cells. Here, we evaluated the possibility that ATP release downstream of caspase-8 via pannexin1 hemichannels (Panx1 HCs) and subsequent activation of P2X(7)Rs participate in FasL-stimulated cell death. Indeed, upon FasL stimulation, ATP was released from Jurkat cells in a time- and caspase-8-dependent manner. Fas and Panx1 HCs colocalized and inhibition of the latter, but not connexin hemichannels, reduced FasL-induced ATP release. Extracellular apyrase, which hydrolyzes ATP, reduced FasL-induced death. Also, oxidized-ATP or Brilliant Blue G, two P2X(7)R blockers, reduced FasL-induced caspase-9 activation and cell death. These results represent the first evidence indicating that the two death receptors, Fas and P2X(7)R connect functionally via caspase-8 and Panx1 HC-mediated ATP release to promote caspase-9/caspase-3-dependent cell death in lymphoid cells. Thus, a hitherto unsuspected route was uncovered connecting the extrinsic to the intrinsic pathway to amplify death signals emanating from the Fas receptor in type II cells. Copyright © 2012 Wiley Periodicals, Inc.

Oncolytic vesicular stomatitis virus induces apoptosis in U87 glioblastoma cells by a type II death receptor mechanism and induces cell death and tumor clearance in vivo.

PubMed

Cary, Zachary D; Willingham, Mark C; Lyles, Douglas S

2011-06-01

Vesicular stomatitis virus (VSV) is a potential oncolytic virus for treating glioblastoma multiforme (GBM), an aggressive brain tumor. Matrix (M) protein mutants of VSV have shown greater selectivity for killing GBM cells versus normal brain cells than VSV with wild-type M protein. The goal of this research was to determine the contribution of death receptor and mitochondrial pathways to apoptosis induced by an M protein mutant (M51R) VSV in U87 human GBM tumor cells. Compared to controls, U87 cells expressing a dominant negative form of Fas (dnFas) or overexpressing Bcl-X(L) had reduced caspase-3 activation following infection with M51R VSV, indicating that both the death receptor pathway and mitochondrial pathways are important for M51R VSV-induced apoptosis. Death receptor signaling has been classified as type I or type II, depending on whether signaling is independent (type I) or dependent on the mitochondrial pathway (type II). Bcl-X(L) overexpression inhibited caspase activation in response to a Fas-inducing antibody, similar to the inhibition in response to M51R VSV infection, indicating that U87 cells behave as type II cells. Inhibition of apoptosis in vitro delayed, but did not prevent, virus-induced cell death. Murine xenografts of U87 cells that overexpress Bcl-X(L) regressed with a time course similar to that of control cells following treatment with M51R VSV, and tumors were not detectable at 21 days postinoculation. Immunohistochemical analysis demonstrated similar levels of viral antigen expression but reduced activation of caspase-3 following virus treatment of Bcl-X(L)-overexpressing tumors compared to controls. Further, the pathological changes in tumors following treatment with virus were quite different in the presence versus the absence of Bcl-X(L) overexpression. These results demonstrate that M51R VSV efficiently induces oncolysis in GBM tumor cells despite deregulation of apoptotic pathways, underscoring its potential use as a treatment for

P2X receptors in the cardiovascular system and their potential as therapeutic targets in disease.

PubMed

Ralevic, Vera

2015-01-01

This review considers the expression and roles of P2X receptors in the cardiovascular system in health and disease and their potential as therapeutic targets. P2X receptors are ligand gated ion channels which are activated by the endogenous ligand ATP. They are formed from the assembly of three P2X subunit proteins from the complement of seven (P2X1-7), which can associate to form homomeric or heteromeric P2X receptors. The P2X1 receptor is widely expressed in the cardiovascular system, being located in the heart, in the smooth muscle of the majority of blood vessels and in platelets. P2X1 receptors expressed in blood vessels can be activated by ATP coreleased with noradrenaline as a sympathetic neurotransmitter, leading to smooth muscle depolarisation and contraction. There is evidence that the purinergic component of sympathetic neurotransmission is increased in hypertension, identifying P2X1 receptors as a possible therapeutic target in this disorder. P2X3 and P2X2/3 receptors are expressed on cardiac sympathetic neurones and may, through positive feedback of neuronal ATP at this prejunctional site, amplify sympathetic neurotransmission. Activation of P2X receptors expressed in the heart increases cardiac myocyte contractility, and an important role of the P2X4 receptor in this has been identified. Deletion of P2X4 receptors in the heart depresses contractile performance in models of heart failure, while overexpression of P2X4 receptors has been shown to be cardioprotective, thus P2X4 receptors may be therapeutic targets in the treatment of heart disease. P2X receptors have been identified on endothelial cells. Although immunoreactivity for all P2X1-7 receptor proteins has been shown on the endothelium, relatively little is known about their function, with the exception of the endothelial P2X4 receptor, which has been shown to mediate endothelium-dependent vasodilatation to ATP released during shear stress. The potential of P2X receptors as therapeutic targets

Prostaglandins and Their Receptors in Eosinophil Function and As Therapeutic Targets

PubMed Central

Peinhaupt, Miriam; Sturm, Eva M.; Heinemann, Akos

2017-01-01

Of the known prostanoid receptors, human eosinophils express the prostaglandin D2 (PGD2) receptors DP1 [also D-type prostanoid (DP)] and DP2 (also chemoattractant receptor homologous molecule, expressed on Th2 cells), the prostaglandin E2 receptors EP2 and EP4, and the prostacyclin (PGI2) receptor IP. Prostanoids can bind to either one or multiple receptors, characteristically have a short half-life in vivo, and are quickly degraded into metabolites with altered affinity and specificity for a given receptor subtype. Prostanoid receptors signal mainly through G proteins and naturally activate signal transduction pathways according to the G protein subtype that they preferentially interact with. This can lead to the activation of sometimes opposing signaling pathways. In addition, prostanoid signaling is often cell-type specific and also the combination of expressed receptors can influence the outcome of the prostanoid impulse. Accordingly, it is assumed that eosinophils and their (patho-)physiological functions are governed by a sensitive prostanoid signaling network. In this review, we specifically focus on the functions of PGD2, PGE2, and PGI2 and their receptors on eosinophils. We discuss their significance in allergic and non-allergic diseases and summarize potential targets for drug intervention. PMID:28770200

Pore-forming toxin-mediated ion dysregulation leads to death receptor-independent necroptosis of lung epithelial cells during bacterial pneumonia

PubMed Central

González-Juarbe, Norberto; Bradley, Kelley Margaret; Shenoy, Anukul Taranath; Gilley, Ryan Paul; Reyes, Luis Felipe; Hinojosa, Cecilia Anahí; Restrepo, Marcos Ignacio; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

2017-01-01

We report that pore-forming toxins (PFTs) induce respiratory epithelial cell necroptosis independently of death receptor signaling during bacterial pneumonia. Instead, necroptosis was activated as a result of ion dysregulation arising from membrane permeabilization. PFT-induced necroptosis required RIP1, RIP3 and MLKL, and could be induced in the absence or inhibition of TNFR1, TNFR2 and TLR4 signaling. We detected activated MLKL in the lungs from mice and nonhuman primates experiencing Serratia marcescens and Streptococcus pneumoniae pneumonia, respectively. We subsequently identified calcium influx and potassium efflux as the key initiating signals responsible for necroptosis; also that mitochondrial damage was not required for necroptosis activation but was exacerbated by MLKL activation. PFT-induced necroptosis in respiratory epithelial cells did not involve CamKII or reactive oxygen species. KO mice deficient in MLKL or RIP3 had increased survival and reduced pulmonary injury during S. marcescens pneumonia. Our results establish necroptosis as a major cell death pathway active during bacterial pneumonia and that necroptosis can occur without death receptor signaling. PMID:28387756

Pore-forming toxin-mediated ion dysregulation leads to death receptor-independent necroptosis of lung epithelial cells during bacterial pneumonia.

PubMed

González-Juarbe, Norberto; Bradley, Kelley Margaret; Shenoy, Anukul Taranath; Gilley, Ryan Paul; Reyes, Luis Felipe; Hinojosa, Cecilia Anahí; Restrepo, Marcos Ignacio; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

2017-05-01

We report that pore-forming toxins (PFTs) induce respiratory epithelial cell necroptosis independently of death receptor signaling during bacterial pneumonia. Instead, necroptosis was activated as a result of ion dysregulation arising from membrane permeabilization. PFT-induced necroptosis required RIP1, RIP3 and MLKL, and could be induced in the absence or inhibition of TNFR1, TNFR2 and TLR4 signaling. We detected activated MLKL in the lungs from mice and nonhuman primates experiencing Serratia marcescens and Streptococcus pneumoniae pneumonia, respectively. We subsequently identified calcium influx and potassium efflux as the key initiating signals responsible for necroptosis; also that mitochondrial damage was not required for necroptosis activation but was exacerbated by MLKL activation. PFT-induced necroptosis in respiratory epithelial cells did not involve CamKII or reactive oxygen species. KO mice deficient in MLKL or RIP3 had increased survival and reduced pulmonary injury during S. marcescens pneumonia. Our results establish necroptosis as a major cell death pathway active during bacterial pneumonia and that necroptosis can occur without death receptor signaling.

Inducing cell death in vitro in cancer cells by targeted delivery of cytochrome c via a transferrin conjugate

PubMed Central

Delgado, Yamixa; Sharma, Rohit Kumar; Sharma, Shweta; Guzmán, Solimar Liz Ponce De León; Tinoco, Arthur D.; Griebenow, Kai

2018-01-01

One of the major drawbacks of many of the currently used cancer drugs are off-target effects. Targeted delivery is one method to minimize such unwanted and detrimental events. To actively target lung cancer cells, we have developed a conjugate of the apoptosis inducing protein cytochrome c with transferrin because the transferrin receptor is overexpressed by many rapidly dividing cancer cells. Cytochrome c and transferrin were cross-linked with a redox sensitive disulfide bond for the intra-cellular release of the protein upon endocytosis by the transferrin receptor. Confocal results demonstrated the cellular uptake of the cytochrome c-transferrin conjugate by transferrin receptor overexpressing A549 lung cancer cells. Localization studies further validated that this conjugate escaped the endosome. Additionally, an in vitro assay showed that the conjugate could induce apoptosis by activating caspase-3. The neo-conjugate not only maintained an IC50 value similar to the well known drug cisplatin (50 μM) in A549 cancer cells but also was nontoxic to the normal lung (MRC5) cells. Our neo-conjugate holds promise for future development to target cancers with enhanced transferrin receptor expression. PMID:29649293

Bypassing Protein Corona Issue on Active Targeting: Zwitterionic Coatings Dictate Specific Interactions of Targeting Moieties and Cell Receptors.

PubMed

Safavi-Sohi, Reihaneh; Maghari, Shokoofeh; Raoufi, Mohammad; Jalali, Seyed Amir; Hajipour, Mohammad J; Ghassempour, Alireza; Mahmoudi, Morteza

2016-09-07

Surface functionalization strategies for targeting nanoparticles (NP) to specific organs, cells, or organelles, is the foundation for new applications of nanomedicine to drug delivery and biomedical imaging. Interaction of NPs with biological media leads to the formation of a biomolecular layer at the surface of NPs so-called as "protein corona". This corona layer can shield active molecules at the surface of NPs and cause mistargeting or unintended scavenging by the liver, kidney, or spleen. To overcome this corona issue, we have designed biotin-cysteine conjugated silica NPs (biotin was employed as a targeting molecule and cysteine was used as a zwitterionic ligand) to inhibit corona-induced mistargeting and thus significantly enhance the active targeting capability of NPs in complex biological media. To probe the targeting yield of our engineered NPs, we employed both modified silicon wafer substrates with streptavidin (i.e., biotin receptor) to simulate a target and a cell-based model platform using tumor cell lines that overexpress biotin receptors. In both cases, after incubation with human plasma (thus forming a protein corona), cellular uptake/substrate attachment of the targeted NPs with zwitterionic coatings were significantly higher than the same NPs without zwitterionic coating. Our results demonstrated that NPs with a zwitterionic surface can considerably facilitate targeting yield of NPs and provide a promising new type of nanocarriers in biological applications.

Targeted delivery of anti-tuberculosis drugs to macrophages: targeting mannose receptors

NASA Astrophysics Data System (ADS)

Filatova, L. Yu; Klyachko, N. L.; Kudryashova, E. V.

2018-04-01

The development of systems for targeted delivery of anti-tuberculosis drugs is a challenge of modern biotechnology. Currently, these drugs are encapsulated in a variety of carriers such as liposomes, polymers, emulsions and so on. Despite successful in vitro testing of these systems, virtually no success was achieved in vivo, because of low accessibility of the foci of infection located in alveolar macrophage cells. A promising strategy for increasing the efficiency of therapeutic action of anti-tuberculosis drugs is to encapsulate the agents into mannosylated carriers targeting the mannose receptors of alveolar macrophages. The review addresses the methods for modification of drug substance carriers, such as liposomes and biodegradable polymers, with mannose residues. The use of mannosylated carriers to deliver anti-tuberculosis agents increases the drug circulation time in the blood stream and increases the drug concentration in alveolar macrophage cells. The bibliography includes 113 references.

Formation and biochemical characterization of tube/pelle death domain complexes: critical regulators of postreceptor signaling by the Drosophila toll receptor.

PubMed

Schiffmann, D A; White, J H; Cooper, A; Nutley, M A; Harding, S E; Jumel, K; Solari, R; Ray, K P; Gay, N J

1999-09-07

In Drosophila, the Toll receptor signaling pathway is required for embryonic dorso-ventral patterning and at later developmental stages for innate immune responses. It is thought that dimerization of the receptor by binding of the ligand spätzle causes the formation of a postreceptor activation complex at the cytoplasmic surface of the membrane. Two components of this complex are the adaptor tube and protein kinase pelle. These proteins both have "death domains", protein interaction motifs found in a number of signaling pathways, particularly those involved in apoptotic cell death. It is thought that pelle is bound by tube during formation of the activation complexes, and that this interaction is mediated by the death domains. In this paper, we show using the yeast two-hybrid system that the wild-type tube and pelle death domains bind together. Mutant tube proteins which do not support signaling in the embryo are also unable to bind pelle in the 2-hybrid assay. We have purified proteins corresponding to the death domains of tube and pelle and show that these form corresponding heterodimeric complexes in vitro. Partial proteolysis reveals a smaller core consisting of the minimal death domain sequences. We have studied the tube/pelle interaction with the techniques of surface plasmon resonance, analytical ultracentrifugation and isothermal titration calorimetry. These measurements produce a value of K(d) for the complex of about 0.5 microM.

The sigma-2 receptor as a therapeutic target for drug delivery in triple negative breast cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makvandi, Mehran; Tilahun, Estifanos D.; Lieberman, Brian P.

Background: Triple-negative breast cancer (TNBC) is associated with high relapse rates and increased mortality when compared with other breast cancer subtypes. In contrast to receptor positive breast cancers, there are no approved targeted therapies for TNBC. Identifying biomarkers for TNBC is of high importance for the advancement of patient care. The sigma-2 receptor has been shown to be overexpressed in triple negative breast cancer in vivo and has been characterized as a marker of proliferation. The aim of the present study was to define the sigma-2 receptor as a target for therapeutic drug delivery and biomarker in TNBC. Methods: Three TNBCmore » cell lines were evaluated: MDA-MB-231, HCC1937 and HCC1806. Sigma-2 compounds were tested for pharmacological properties specific to the sigma-2 receptor through competitive inhibition assays. Sigma-2 receptor expression was measured through radioligand receptor saturation studies. Drug sensitivity for taxol was compared to a sigma-2 targeting compound conjugated to a cytotoxic payload, SW IV-134. Cell viability was assessed after treatments for 2 or 48 h. Sigma-2 blockade was assessed to define sigma-2 mediated cytotoxicity of SW IV-134. Caspase 3/7 activation induced by SW IV-134 was measured at corresponding treatment time points. Results: SW IV-134 was the most potent compound tested in two of the three cell lines and was similarly effective in all three. MDA-MB-231 displayed a statistically significant higher sigma-2 receptor expression and also was the most sensitive cell line evaluated to SW IV-134. Conclusion: Targeting the sigma-2 receptor with a cytotoxic payload was effective in all the three cell lines evaluated and provides the proof of concept for future development of a therapeutic platform for the treatment of TNBC. - Highlights: • TNBC cells are sensitive to sigma-2 receptor targeted drug conjugate SW IV-134. • MDA-MB-231 displayed the highest amount of sigma-2 receptors and corresponded well

Lubiprostone targets prostanoid EP4 receptors in ovine airways

PubMed Central

Cuthbert, AW

2011-01-01

BACKGROUND AND PURPOSE Lubiprostone, a prostaglandin E1 derivative, is reported to activate ClC-2 chloride channels located in the apical membranes of a number of transporting epithelia. Lack of functioning CFTR chloride channels in epithelia is responsible for the genetic disease cystic fibrosis, therefore, surrogate channels that can operate independently of CFTR are of interest. This study explores the target receptor(s) for lubiprostone in airway epithelium. EXPERIMENTAL APPROACH All experiments were performed on the ventral tracheal epithelium of sheep. Epithelia were used to measure anion secretion from the apical surface as short circuit current or as fluid secretion from individual airway submucosal glands, using an optical method. KEY RESULTS The EP4 antagonists L-161982 and GW627368 inhibited short circuit current responses to lubiprostone, while EP1,2&3 receptor antagonists were without effect. Similarly, lubiprostone induced secretion in airway submucosal glands was inhibited by L-161982. L-161982 effectively competed with lubiprostone with a Kd value of 0.058 µM, close to its value for binding to human EP4 receptors (0.024 µM). The selective EP4 agonist L-902688 and lubiprostone behaved similarly with respect to EP4 receptor antagonists. Results of experiments with H89, a protein kinase A inhibitor, were consistent with lubiprostone acting through a Gs-protein coupled EP4 receptor/cAMP cascade. CONCLUSIONS AND IMPLICATIONS Lubiprostone-induced short-circuit currents and submucosal gland secretions were inhibited by selective EP4 receptor antagonists. The results suggest EP4 receptor activation by lubiprostone triggers cAMP production necessary for CFTR activation and the secretory responses, a possibility precluded in CF tissues. PMID:20883477

Brain-Targeted (Pro)Renin Receptor Knockdown attenuates Angiotensin II-Dependent Hypertension

PubMed Central

Li, Wencheng; Peng, Hua; Cao, Theresa; Sato, Ryosuke; McDaniels, Sarah. J.; Kobori, Hiroyuki; Navar, L. Gabriel; Feng, Yumei

2012-01-01

The (pro)renin receptor is a newly discovered member of the brain renin-angiotensin system. To investigate the role of brain (pro)renin receptor in hypertension, adeno-associated virus-mediated (pro)renin receptor shRNA was used to knockdown (pro)renin receptor expression in the brain of non-transgenic normotensive and human renin-angiotensinogen double transgenic hypertensive mice. Blood pressure was monitored using implanted telemetric probes in conscious animals. Real-time PCR and immunostaining were performed to determine (pro)renin receptor, angiotensin II type 1 receptor and vasopressin mRNA levels. Plasma vasopressin levels were determined by Enzyme-Linked Immuno Sorbent Assay. Double transgenic mice exhibited higher blood pressure, elevated cardiac and vascular sympathetic tone, and impaired spontaneous baroreflex sensitivity. Intracerebroventricular delivery of (pro)renin receptor shRNA significantly reduced blood pressure, cardiac and vasomotor sympathetic tone, and improved baroreflex sensitivity compared to the control virus treatment in double transgenic mice. (Pro)renin receptor knockdown significantly reduced angiotensin II type 1 receptor and vasopressin levels in double transgenic mice. These data indicate that (pro)renin receptor knockdown in the brain attenuates angiotensin II-dependent hypertension and is associated with a decrease insympathetic tone and an improvement of the baroreflex sensitivity. In addition, brain-targeted (pro)renin receptor knockdown is associated with down-regulation of angiotensin II type 1 receptor and vasopressin levels. We conclude that central (pro)renin receptor contributes to the pathogenesis of hypertension in human renin-angiotensinogen transgenic mice. PMID:22526255

Free fatty acid receptors: emerging targets for treatment of diabetes and its complications

PubMed Central

Vangaveti, Venkat; Shashidhar, Venkatesh; Jarrod, Ghassan; Baune, Bernhard T.; Kennedy, R. Lee

2010-01-01

Fatty acids (FAs) are important as metabolic substrates and as structural components of biological membranes. However, they also function as signalling molecules. Recently, a series of G protein-coupled receptors (GPRs) for FAs has been described and characterized. These receptors have differing specificities for FAs of differing chain length and degree of saturation, for FA derivatives such as oleoylethanolamide, and for oxidized FAs. They are a critical component of the body's nutrient sensing apparatus, and small molecule agonists and antagonists of these receptors show considerable promise in the management of diabetes and its complications. Agonists of the long-chain free fatty acid receptors FFAR1 and GPR119 act as insulin secretagogues, both directly and by increasing incretins. Although, drugs acting at short-chain FFA receptors (FFAR2 and FFAR3) have not yet been developed, they are attractive targets as they regulate nutrient balance through effects in the intestine and adipose tissue. These include regulation of the secretion of cholecystokinin, peptide YY and leptin. Finally, GPR132 is a receptor for oxidized FAs, which may be a sensor of lipid overload and oxidative stress, and which is involved in atherosclerosis. Regulation of its signalling pathways with drugs may decrease the macrovascular risk experienced by diabetic patients. In summary, FA receptors are emerging drug targets that are involved in the regulation of nutrient status and carbohydrate tolerance, and modulators of these receptors may well figure prominently in the next generation of antidiabetic drugs. PMID:23148161

Targeting Epidermal Growth Factor Receptor-Related Signaling Pathways in Pancreatic Cancer.

PubMed

Philip, Philip A; Lutz, Manfred P

2015-10-01

Pancreatic cancer is aggressive, chemoresistant, and characterized by complex and poorly understood molecular biology. The epidermal growth factor receptor (EGFR) pathway is frequently activated in pancreatic cancer; therefore, it is a rational target for new treatments. However, the EGFR tyrosine kinase inhibitor erlotinib is currently the only targeted therapy to demonstrate a very modest survival benefit when added to gemcitabine in the treatment of patients with advanced pancreatic cancer. There is no molecular biomarker to predict the outcome of erlotinib treatment, although rash may be predictive of improved survival; EGFR expression does not predict the biologic activity of anti-EGFR drugs in pancreatic cancer, and no EGFR mutations are identified as enabling the selection of patients likely to benefit from treatment. Here, we review clinical studies of EGFR-targeted therapies in combination with conventional cytotoxic regimens or multitargeted strategies in advanced pancreatic cancer, as well as research directed at molecules downstream of EGFR as alternatives or adjuncts to receptor targeting. Limitations of preclinical models, patient selection, and trial design, as well as the complex mechanisms underlying resistance to EGFR-targeted agents, are discussed. Future clinical trials must incorporate translational research end points to aid patient selection and circumvent resistance to EGFR inhibitors.

Anticancer activity of the type I insulin-like growth factor receptor antagonist, ganitumab, in combination with the death receptor 5 agonist, conatumumab.

PubMed

Tabernero, Josep; Chawla, Sant P; Kindler, Hedy; Reckamp, Karen; Chiorean, E Gabriela; Azad, Nilofer S; Lockhart, A Craig; Hsu, Cheng-Pang; Baker, Nigel F; Galimi, Francesco; Beltran, Pedro; Baselga, José

2015-03-01

Agents targeting the insulin-like growth factor receptor type 1 (IGF1R) have shown antitumor activity. Based on the evidence for interaction between the IGF-1 and TRAIL pathways, we hypothesized that the combination of ganitumab (monoclonal antibody to IGF1R) with the pro-apoptotic death receptor 5 agonist, conatumumab, might increase antitumor response. Ganitumab and conatumumab were tested in combination in a Colo-205 xenograft model. Part 1 of the clinical study was a phase Ib program of three doses of conatumumab (1, 3, 15 mg/kg) in combination with 18 mg/kg ganitumab to determine the maximum tolerated dose (MTD) in patients with advanced solid tumors. Part 2 was conducted in six cohorts with advanced non-small cell lung cancer (squamous or non-squamous histology), colorectal cancer, sarcoma, pancreatic cancer, or ovarian cancer, treated at the recommended doses of the combination. The combination was significantly more active in the Colo-205 xenograft model than either single agent alone (p < 0.0015). In part 1 of the clinical study, no dose-limiting toxicities were observed and the MTD of conatumumab was 15 mg/kg in combination with 18 mg/kg ganitumab. In part 2, 78 patients were treated and there were no objective responses but 28 patients (36 %) had stable disease (median 46 days, range 0-261). The combination was well-tolerated with no new toxicities. In conclusion, the combination of ganitumab and conatumumab was well-tolerated but had no objective responses in the population tested. The successful future application of this combination of antitumor mechanisms may rely on the identification of predictive biomarkers.

Targeting the androgen receptor in prostate and breast cancer – several new agents in development

PubMed Central

Proverbs-Singh, Tracy; Feldman, Jarett L.; Morris, Michael J.; Autio, Karen A.; Traina, Tiffany A.

2016-01-01

Prostate cancer and breast cancer share similarities as hormone-sensitive cancers with a wide heterogeneity of both phenotype and biology. The androgen receptor (AR) is a hormone receptor involved in both benign and malignant processes. Targeting androgen synthesis and the AR pathway has been and remains central to prostate cancer therapy. Recently, there is increased interest in the role of the AR in breast cancer development and growth, with data suggesting AR co-expression with estrogen, progesterone and human epidermal growth factor receptors, across all intrinsic subtypes of breast cancer. Targeting the AR axis is an evolving field with novel therapies in development which may ultimately be applicable for both tumor types. In this review, we offer an overview of available agents which target the AR axis in both prostate and breast cancer and provide insight into the novel drugs in development for targeting this signaling pathway. PMID:25722318

A Multi-Receptor and Multi-Species Assay for Potential Endocrine Disruptor Targets (SLAS meeting)

EPA Science Inventory

Screening methods for detecting potential endocrine disrupting chemicals rely chiefly on transactivation assays targeting nuclear receptors such as the estrogen (ER) and androgen receptors (AR). These assays are predominately human-based; yet environmental exposure can affect div...

Catalytically active Yersinia outer protein P induces cleavage of RIP and caspase-8 at the level of the DISC independently of death receptors in dendritic cells.

PubMed

Gröbner, Sabine; Adkins, Irena; Schulz, Sebastian; Richter, Kathleen; Borgmann, Stefan; Wesselborg, Sebastian; Ruckdeschel, Klaus; Micheau, Olivier; Autenrieth, Ingo B

2007-10-01

Yersinia outer protein P (YopP) is injected by Y. enterocolitica into host cells thereby inducing apoptotic and necrosis-like cell death in dendritic cells (DC). Here we show the pathways involved in DC death caused by the catalytic activity of YopP. Infection with Yersinia enterocolitica, translocating catalytically active YopP into DC, triggered procaspase-8 cleavage and c-FLIPL degradation. YopP-dependent caspase-8 activation was, however, not mediated by tumor necrosis factor (TNF) receptor family members since the expression of both CD95/Fas/APO-1 and TRAIL-R2 on DC was low, and DC were resistant to apoptosis induced by agonistic anti-CD95 antibodies or TNF-related apoptosis-inducing ligand (TRAIL). Moreover, DC from TNF-Rp55-/- mice were not protected against YopP-induced cell death demonstrating that TNF-R1 is also not involved in this process. Activation of caspase-8 was further investigated by coimmunoprecitation of FADD from Yersinia-infected DC. We found that both cleaved caspase-8 and receptor interacting protein 1 (RIP1) were associated with the Fas-associated death domain (FADD) indicating the formation of an atypical death-inducing signaling complex (DISC). Furthermore, degradation of RIP mediated by the Hsp90 inhibitor geldanamycin significantly impaired YopP-induced cell death. Altogether our findings indicate that Yersinia-induced DC death is independent of death domain containing receptors, but mediated by RIP and caspase-8 at the level of DISC.

Insertion/deletion polymorphism in alpha2-adrenergic receptor gene is a genetic risk factor for sudden cardiac death.

PubMed

Laukkanen, Jari A; Mäkikallio, Timo H; Kauhanen, Jussi; Kurl, Sudhir

2009-10-01

Adrenoceptors mediate contraction of vascular smooth muscle and induce coronary vasoconstriction in humans. A deletion variant of the human alpha(2B)-adrenoreseptor of glutamic acid residues has been associated with impaired receptor desensitization. This receptor variant could, therefore, be involved in cardiovascular diseases associated with enhanced vasoconstriction. Our aim was to study whether an insertion/deletion (I/D) polymorphism in the alpha(2B)-adrenoceptor gene is associated with the risk for sudden cardiac death. This was a prospective population-based study investigating risk factors for cardiovascular diseases in middle-aged men from 42 to 60 years from eastern Finland. The study is based on 1,606 men with complete data on DNA observed for an average time of 17 years. In this study population, 338 men (21%) had the D/D genotype, 467 (29%) had the I/I genotype, and 801 (50%) had a heterozygous genotype. There were 76 sudden cardiac deaths during follow-up (0.81 deaths/1,000 persons per year). In a Cox model adjusting for other coronary risk factors (age, systolic blood pressure, smoking, diabetes, serum low-density lipoprotein and high-density lipoprotein cholesterol, body mass index, and exercise-induced myocardial ischemia), men with the D/D or I/D genotype had 1.97 times (95% CI 1.08-3.59, P = .026) higher risk to experience sudden cardiac death (20 events for D/D genotype, 13 events for I/I genotype, and 43 events for I/D genotype) compared with men carrying the I/I genotype. In addition, the alpha(2B)-adrenoceptor D/D genotype was associated with the risk of coronary heart disease death and acute coronary events, after adjusting for risk factors. The genetic polymorphism of the alpha(2B)-adrenoreceptor is genetic risk predictor for sudden cardiac death.

Synthesis and exploration of novel radiolabeled bombesin peptides for targeting receptor positive tumor.

PubMed

De, Kakali; Banerjee, Indranil; Sinha, Samarendu; Ganguly, Shantanu

2017-03-01

Increasing evidence of peptide receptor overexpression in various cancer cells, warrant the development of receptor specific radiolabeled peptides for molecular imaging and therapy in nuclear medicine. Gastrin-releasing-peptide (GRP) receptor, are overexpressed in a variety of human cancer cells. The present study report the synthesis and biological evaluation of new bombesin (BBN) analogs, HYNIC-Asp-[Phe 13 ]BBN(7-13)-NH-CH 2 -CH 2 -CH3:BA1, HYNIC-Pro-[Tyr 13 Met 14 ]BBN(7-14)NH 2 :BA2 as prospective tumor imaging agent with compare to BBN(7-14)NH 2 :BS as standard. The pharmacophores were radiolabeled in high yields with 99m Tc, characterized for their stability in serum and saline, cysteine/histidine and were found to be substantially stable. Internalization/externalization and receptor binding studies were assessed using MDA-MB-231 cells and showed high receptor binding-affinity and favourable internalization. Fluorescence studies revealed that BA1 changed the morphology of the cells and could localize in the nucleus more effectively than BA2/BS. Cell-viability studies displayed substantial antagonistic and nuclear-internalization effect of BA1. BA1 also exhibited antiproliferative effect on MDA-MB-231 cell by inducing apoptosis. In vivo behaviour of the radiopeptides was evaluated in GRP receptor positive tumor bearing mice. The 99m Tc-BA1/ 99m Tc-BA2 demonstrated rapid blood/urinary clearance through the renal pathway and comparatively more significant tumor uptake image and favourable tumor-to-non-target ratios provided by 99m Tc-BA1. The specificity of the in vivo uptake was confirmed by co-injection with BS. Moreover, 99m Tc-BA1 provided a much clearer tumor image in scintigraphic studies than others. Thus the combination of favourable in vitro and in vivo properties renders BA1 as more potential antagonist bombesin-peptide for targeting GRP-receptor positive tumor. These properties are encouraging to carry out further experiments for non-invasive receptor

Selective targeting of a TNFR decoy receptor pharmaceutical to the primate brain as a receptor-specific IgG fusion protein.

PubMed

Boado, Ruben J; Hui, Eric Ka-Wai; Lu, Jeff Zhiqiang; Zhou, Qing-Hui; Pardridge, William M

2010-03-01

Decoy receptors, such as the human tumor necrosis factor receptor (TNFR), are potential new therapies for brain disorders. However, decoy receptors are large molecule drugs that are not transported across the blood-brain barrier (BBB). To enable BBB transport of a TNFR decoy receptor, the human TNFR-II extracellular domain was re-engineered as a fusion protein with a chimeric monoclonal antibody (MAb) against the human insulin receptor (HIR). The HIRMAb acts as a molecular Trojan horse to ferry the TNFR therapeutic decoy receptor across the BBB. The HIRMAb-TNFR fusion protein was expressed in stably transfected CHO cells, and was analyzed with electrophoresis, Western blotting, size exclusion chromatography, and binding assays for the HIR and TNFalpha. The HIRMAb-TNFR fusion protein was radio-labeled by trititation, in parallel with the radio-iodination of recombinant TNFR:Fc fusion protein, and the proteins were co-injected in the adult Rhesus monkey. The TNFR:Fc fusion protein did not cross the primate BBB in vivo, but the uptake of the HIRMAb-TNFR fusion protein was high and 3% of the injected dose was taken up by the primate brain. The TNFR was selectively targeted to brain, relative to peripheral organs, following fusion to the HIRMAb. This study demonstrates that decoy receptors may be re-engineered as IgG fusion proteins with a BBB molecular Trojan horse that selectively targets the brain, and enables penetration of the BBB in vivo. IgG-decoy receptor fusion proteins represent a new class of human neurotherapeutics. Copyright 2010 Elsevier B.V. All rights reserved.

Mechanism-Based Tumor-Targeting Drug Delivery System. Validation of Efficient Vitamin Receptor-Mediated Endocytosis and Drug Release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, S.; Wong, S.; Zhao, X.

An efficient mechanism-based tumor-targeting drug delivery system, based on tumor-specific vitamin-receptor mediated endocytosis, has been developed. The tumor-targeting drug delivery system is a conjugate of a tumor-targeting molecule (biotin: vitamin H or vitamin B-7), a mechanism-based self-immolative linker and a second-generation taxoid (SB-T-1214) as the cytotoxic agent. This conjugate (1) is designed to be (i) specific to the vitamin receptors overexpressed on tumor cell surface and (ii) internalized efficiently through receptor-mediated endocytosis, followed by smooth drug release via glutathione-triggered self-immolation of the linker. In order to monitor and validate the sequence of events hypothesized, i.e., receptor-mediated endocytosis of the conjugate,more » drug release, and drug-binding to the target protein (microtubules), three fluorescent/fluorogenic molecular probes (2, 3, and 4) were designed and synthesized. The actual occurrence of these processes was unambiguously confirmed by means of confocal fluorescence microscopy (CFM) and flow cytometry using L1210FR leukemia cells, overexpressing biotin receptors. The molecular probe 4, bearing the taxoid linked to fluorescein, was also used to examine the cell specificity (i.e., efficacy of receptor-based cell targeting) for three cell lines, L1210FR (biotin receptors overexpressed), L1210 (biotin receptors not overexpressed), and WI38 (normal human lung fibroblast, biotin receptor negative). As anticipated, the molecular probe 4 exhibited high specificity only to L1210FR. To confirm the direct correlation between the cell-specific drug delivery and anticancer activity of the probe 4, its cytotoxicity against these three cell lines was also examined. The results clearly showed a good correlation between the two methods. In the same manner, excellent cell-specific cytotoxicity of the conjugate 1 (without fluorescein attachment to the taxoid) against the same three cell lines was confirmed. This

A compound chimeric antigen receptor strategy for targeting multiple myeloma.

PubMed

Chen, K H; Wada, M; Pinz, K G; Liu, H; Shuai, X; Chen, X; Yan, L E; Petrov, J C; Salman, H; Senzel, L; Leung, E L H; Jiang, X; Ma, Y

2018-02-01

Current clinical outcomes using chimeric-antigen receptors (CARs) against multiple myeloma show promise in the eradication of bulk disease. However, these anti-BCMA (CD269) CARs observe relapse as a common phenomenon after treatment due to the reemergence of either antigen-positive or -negative cells. Hence, the development of improvements in CAR design to target antigen loss and increase effector cell persistency represents a critical need. Here, we report on the anti-tumor activity of a CAR T-cell possessing two complete and independent CAR receptors against the multiple myeloma antigens BCMA and CS1. We determined that the resulting compound CAR (cCAR) T-cell possesses consistent, potent and directed cytotoxicity against each target antigen population. Using multiple mouse models of myeloma and mixed cell populations, we are further able to show superior in vivo survival by directed cytotoxicity against multiple populations compared to a single-expressing CAR T-cell. These findings indicate that compound targeting of BCMA and CS1 on myeloma cells can potentially be an effective strategy for augmenting the response against myeloma bulk disease and for initiation of broader coverage CAR therapy.

Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish.

PubMed

Viringipurampeer, I A; Shan, X; Gregory-Evans, K; Zhang, J P; Mohammadi, Z; Gregory-Evans, C Y

2014-05-01

Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

The ubiquitin-homology protein, DAP-1, associates with tumor necrosis factor receptor (p60) death domain and induces apoptosis.

PubMed

Liou, M L; Liou, H C

1999-04-09

The tumor necrosis factor receptor, p60 (TNF-R1), transduces death signals via the association of its cytoplasmic domain with several intracellular proteins. By screening a mammalian cDNA library using the yeast two-hybrid cloning technique, we isolated a ubiquitin-homology protein, DAP-1, which specifically interacts with the cytoplasmic death domain of TNF-R1. Sequence analysis reveals that DAP-1 shares striking sequence homology with the yeast SMT3 protein that is essential for the maintenance of chromosome integrity during mitosis (Meluh, P. B., and Koshland, D. (1995) Mol. Biol. Cell 6, 793-807). DAP-1 is nearly identical to PIC1, a protein that interacts with the PML tumor suppressor implicated in acute promyelocytic leukemia (Boddy, M. N., Howe, K., Etkin, L. D., Solomon, E., and Freemont, P. S. (1996) Oncogene 13, 971-982), and the sentrin protein, which associates with the Fas death receptor (Okura, T., Gong, L., Kamitani, T., Wada, T., Okura, I., Wei, C. F., Chang, H. M., and Yeh, E. T. (1996) J. Immunol. 157, 4277-4281). The in vivo interaction between DAP-1 and TNF-R1 was further confirmed in mammalian cells. In transient transfection assays, overexpression of DAP-1 suppresses NF-kappaB/Rel activity in 293T cells, a human kidney embryonic carcinoma cell line. Overexpression of either DAP-1 or sentrin causes apoptosis of TNF-sensitive L929 fibroblast cell line, as well as TNF-resistant osteosarcoma cell line, U2OS. Furthermore, the dominant negative Fas-associated death domain protein (FADD) protein blocks the cell death induced by either DAP-1 or FADD. Collectively, these observations highly suggest a role for DAP-1 in mediating TNF-induced cell death signaling pathways, presumably through the recruitment of FADD death effector.

The Insulin Receptor: A New Target for Cancer Therapy

PubMed Central

Malaguarnera, Roberta; Belfiore, Antonino

2011-01-01

A large body of evidences have shown that both the IGF-I receptor (IGF-IR) and the insulin receptor (IR) play a role in cancer development and progression. In particular, IR overactivation by IGF-II is common in cancer cells, especially in dedifferentiated/stem-like cells. In spite of these findings, until very recently, only IGF-IR but not IR has been considered a target in cancer therapy. Although several preclinical studies have showed a good anti-cancer activity of selective anti-IGF-IR drugs, the results of the clinical first trials have been disappointing. In fact, only a small subset of malignant tumors has shown an objective response to these therapies. Development of resistance to anti-IGF-IR drugs may include upregulation of IR isoform A (IR-A) in cancer cells and its overactivation by increased secretion of autocrine IGF-II. These findings have led to the concept that co-targeting IR together with IGF-IR may increase therapy efficacy and prevent adaptive resistance to selective anti-IGF-IR drugs. IR blockade should be especially considered in tumors with high IR-A:IGF-IR ratio and high levels of autocrine IGF-II. Conversely, insulin sensitizers, which ameliorate insulin resistance associated with metabolic disorders and cancer treatments, may have important implications for cancer prevention and management. Only few drugs co-targeting the IR and IGF-IR are currently available. Ideally, future IR targeting strategies should be able to selectively inhibit the tumor promoting effects of IR without impairing its metabolic effects. PMID:22654833

Cardioprotective activity of urocortin by preventing caspase-independent, non-apoptotic death in cultured neonatal rat cardiomyocytes exposed to ischemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takatani-Nakase, Tomoka, E-mail: nakase@mukogawa-u.ac.jp; Takahashi, Koichi, E-mail: koichi@mukogawa-u.ac.jp

Research highlights: {yields} Ischemia induces high level of iPLA{sub 2} resulting in caspase-independent myocyte death. {yields} Urocortin causes iPLA{sub 2} down-regulation leading to avoidance of non-apoptotic death. {yields} The survival-promoting effect of urocortin is abrogated by CRH receptor antagonist. -- Abstract: Caspase-independent, non-apoptotic cell death in ischemic heart disease is considered to be one of the important therapeutic targets, however, the detailed mechanisms of this cell death process are not clear. In this study, we investigated the mechanisms of non-apoptotic cell death in cultured neonatal rat cardiomyocytes during ischemia, and the cardioprotection by preventing the mechanisms. We found that ischemiamore » caused elevation of the phospholipase A{sub 2} (iPLA{sub 2}) expression in the myocytes, leading to distinctive non-apoptotic nuclear shrinkage, and cell death. Moreover, we investigated whether the potent cardioprotective corticotropin-releasing hormone (CRH), urocortin, which had been less focused on non-apoptotic cell death, inhibits the ischemic myocyte death. Ischemia-augmented nuclear shrinkage of the myocytes was suppressed by the pretreatment of {approx}10 nM urocortin before the cells were exposed to ischemia. Urocortin could significantly suppress the expression and activity of iPLA{sub 2}, resulting in preventing the ischemia-induced cell death. The survival-promoting effect of urocortin was abrogated by the CRH receptor antagonist astressin. These findings provide the first evidence linking the targets of the urocortin-mediated cardioprotection to the suppression of the caspase-independent, non-apoptotic death in cardiac myocytes exposed to ischemia.« less

DNA targeting of rhinal cortex D2 receptor protein reversibly blocks learning of cues that predict reward.

PubMed

Liu, Zheng; Richmond, Barry J; Murray, Elisabeth A; Saunders, Richard C; Steenrod, Sara; Stubblefield, Barbara K; Montague, Deidra M; Ginns, Edward I

2004-08-17

When schedules of several operant trials must be successfully completed to obtain a reward, monkeys quickly learn to adjust their behavioral performance by using visual cues that signal how many trials have been completed and how many remain in the current schedule. Bilateral rhinal (perirhinal and entorhinal) cortex ablations irreversibly prevent this learning. Here, we apply a recombinant DNA technique to investigate the role of dopamine D2 receptor in rhinal cortex for this type of learning. Rhinal cortex was injected with a DNA construct that significantly decreased D2 receptor ligand binding and temporarily produced the same profound learning deficit seen after ablation. However, unlike after ablation, the D2 receptor-targeted, DNA-treated monkeys recovered cue-related learning after 11-19 weeks. Injecting a DNA construct that decreased N-methyl-d-aspartate but not D2 receptor ligand binding did not interfere with learning associations between the cues and the schedules. A second D2 receptor-targeted DNA treatment administered after either recovery from a first D2 receptor-targeted DNA treatment (one monkey), after N-methyl-d-aspartate receptor-targeted DNA treatment (two monkeys), or after a vector control treatment (one monkey) also induced a learning deficit of similar duration. These results suggest that the D2 receptor in primate rhinal cortex is essential for learning to relate the visual cues to the schedules. The specificity of the receptor manipulation reported here suggests that this approach could be generalized in this or other brain pathways to relate molecular mechanisms to cognitive functions.

DNA targeting of rhinal cortex D2 receptor protein reversibly blocks learning of cues that predict reward

PubMed Central

Liu, Zheng; Richmond, Barry J.; Murray, Elisabeth A.; Saunders, Richard C.; Steenrod, Sara; Stubblefield, Barbara K.; Montague, Deidra M.; Ginns, Edward I.

2004-01-01

When schedules of several operant trials must be successfully completed to obtain a reward, monkeys quickly learn to adjust their behavioral performance by using visual cues that signal how many trials have been completed and how many remain in the current schedule. Bilateral rhinal (perirhinal and entorhinal) cortex ablations irreversibly prevent this learning. Here, we apply a recombinant DNA technique to investigate the role of dopamine D2 receptor in rhinal cortex for this type of learning. Rhinal cortex was injected with a DNA construct that significantly decreased D2 receptor ligand binding and temporarily produced the same profound learning deficit seen after ablation. However, unlike after ablation, the D2 receptor-targeted, DNA-treated monkeys recovered cue-related learning after 11–19 weeks. Injecting a DNA construct that decreased N-methyl-d-aspartate but not D2 receptor ligand binding did not interfere with learning associations between the cues and the schedules. A second D2 receptor-targeted DNA treatment administered after either recovery from a first D2 receptor-targeted DNA treatment (one monkey), after N-methyl-d-aspartate receptor-targeted DNA treatment (two monkeys), or after a vector control treatment (one monkey) also induced a learning deficit of similar duration. These results suggest that the D2 receptor in primate rhinal cortex is essential for learning to relate the visual cues to the schedules. The specificity of the receptor manipulation reported here suggests that this approach could be generalized in this or other brain pathways to relate molecular mechanisms to cognitive functions. PMID:15302926

Loss of diphthamide pre-activates NF-κB and death receptor pathways and renders MCF7 cells hypersensitive to tumor necrosis factor.

PubMed

Stahl, Sebastian; da Silva Mateus Seidl, Ana Rita; Ducret, Axel; Kux van Geijtenbeek, Sabine; Michel, Sven; Racek, Tomas; Birzele, Fabian; Haas, Alexander K; Rueger, Ruediger; Gerg, Michael; Niederfellner, Gerhard; Pastan, Ira; Brinkmann, Ulrich

2015-08-25

The diphthamide on human eukaryotic translation elongation factor 2 (eEF2) is the target of ADP ribosylating diphtheria toxin (DT) and Pseudomonas exotoxin A (PE). This modification is synthesized by seven dipthamide biosynthesis proteins (DPH1-DPH7) and is conserved among eukaryotes and archaea. We generated MCF7 breast cancer cell line-derived DPH gene knockout (ko) cells to assess the impact of complete or partial inactivation on diphthamide synthesis and toxin sensitivity, and to address the biological consequence of diphthamide deficiency. Cells with heterozygous gene inactivation still contained predominantly diphthamide-modified eEF2 and were as sensitive to PE and DT as parent cells. Thus, DPH gene copy number reduction does not affect overall diphthamide synthesis and toxin sensitivity. Complete inactivation of DPH1, DPH2, DPH4, and DPH5 generated viable cells without diphthamide. DPH1ko, DPH2ko, and DPH4ko harbored unmodified eEF2 and DPH5ko ACP- (diphthine-precursor) modified eEF2. Loss of diphthamide prevented ADP ribosylation of eEF2, rendered cells resistant to PE and DT, but does not affect sensitivity toward other protein synthesis inhibitors, such as saporin or cycloheximide. Surprisingly, cells without diphthamide (independent of which the DPH gene compromised) were presensitized toward nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) and death-receptor pathways without crossing lethal thresholds. In consequence, loss of diphthamide rendered cells hypersensitive toward TNF-mediated apoptosis. This finding suggests a role of diphthamide in modulating NF-κB, death receptor, or apoptosis pathways.

Peptide drugs to target G protein-coupled receptors.

PubMed

Bellmann-Sickert, Kathrin; Beck-Sickinger, Annette G

2010-09-01

Major indications for use of peptide-based therapeutics include endocrine functions (especially diabetes mellitus and obesity), infectious diseases, and cancer. Whereas some peptide pharmaceuticals are drugs, acting as agonists or antagonists to directly treat cancer, others (including peptide diagnostics and tumour-targeting pharmaceuticals) use peptides to 'shuttle' a chemotherapeutic agent or a tracer to the tumour and allow sensitive imaging or targeted therapy. Significant progress has been made in the last few years to overcome disadvantages in peptide design such as short half-life, fast proteolytic cleavage, and low oral bioavailability. These advances include peptide PEGylation, lipidisation or multimerisation; the introduction of peptidomimetic elements into the sequences; and innovative uptake strategies such as liposomal, capsule or subcutaneous formulations. This review focuses on peptides targeting G protein-coupled receptors that are promising drug candidates or that have recently entered the pharmaceutical market. Copyright 2010 Elsevier Ltd. All rights reserved.

Shedding of Microvesicles from Microglia Contributes to the Effects Induced by Metabotropic Glutamate Receptor 5 Activation on Neuronal Death.

PubMed

Beneventano, Martina; Spampinato, Simona F; Merlo, Sara; Chisari, Mariangela; Platania, Paola; Ragusa, Marco; Purrello, Michele; Nicoletti, Ferdinando; Sortino, Maria Angela

2017-01-01

Metabotropic glutamate (mGlu) receptor 5 is involved in neuroinflammation and has been shown to mediate reduced inflammation and neurotoxicity and to modify microglia polarization. On the other hand, blockade of mGlu5 receptor results in inhibition of microglia activation. To dissect this controversy, we investigated whether microvesicles (MVs) released from microglia BV2 cells could contribute to the communication between microglia and neurons and whether this interaction was modulated by mGlu5 receptor. Activation of purinergic ionotropic P2X7 receptor with the stable ATP analog benzoyl-ATP (100 μM) caused rapid MVs shedding from BV2 cells. Ionic currents through P2X7 receptor increased in BV2 cells pretreated for 24 h with the mGlu5 receptor agonist CHPG (200 μM) as by patch-clamp recording. This increase was blunted when microglia cells were activated by exposure to lipopolysaccharide (LPS; 0.1 μg/ml for 6 h). Accordingly, a greater amount of MVs formed after CHPG treatment, an effect prevented by the mGlu5 receptor antagonist MTEP (100 μM), as measured by expression of flotillin, a membrane protein enriched in MVs. Transferred MVs were internalized by SH-SY5Y neurons where they did not modify neuronal death induced by a low concentration of rotenone (0.1 μM for 24 h), but significantly increased rotenone neurotoxicity when shed from CHPG-treated BV2 cells. miR146a was increased in CHPG-treated MVs, an effect concealed in MVs from LPS-activated BV2 cells that showed per se an increase in miRNA146a levels. The present data support a role for microglia-shed MVs in mGlu5-mediated modulation of neuronal death and identify miRNAs as potential critical mediators of this interaction.

Shedding of Microvesicles from Microglia Contributes to the Effects Induced by Metabotropic Glutamate Receptor 5 Activation on Neuronal Death

PubMed Central

Beneventano, Martina; Spampinato, Simona F.; Merlo, Sara; Chisari, Mariangela; Platania, Paola; Ragusa, Marco; Purrello, Michele; Nicoletti, Ferdinando; Sortino, Maria Angela

2017-01-01

Metabotropic glutamate (mGlu) receptor 5 is involved in neuroinflammation and has been shown to mediate reduced inflammation and neurotoxicity and to modify microglia polarization. On the other hand, blockade of mGlu5 receptor results in inhibition of microglia activation. To dissect this controversy, we investigated whether microvesicles (MVs) released from microglia BV2 cells could contribute to the communication between microglia and neurons and whether this interaction was modulated by mGlu5 receptor. Activation of purinergic ionotropic P2X7 receptor with the stable ATP analog benzoyl-ATP (100 μM) caused rapid MVs shedding from BV2 cells. Ionic currents through P2X7 receptor increased in BV2 cells pretreated for 24 h with the mGlu5 receptor agonist CHPG (200 μM) as by patch-clamp recording. This increase was blunted when microglia cells were activated by exposure to lipopolysaccharide (LPS; 0.1 μg/ml for 6 h). Accordingly, a greater amount of MVs formed after CHPG treatment, an effect prevented by the mGlu5 receptor antagonist MTEP (100 μM), as measured by expression of flotillin, a membrane protein enriched in MVs. Transferred MVs were internalized by SH-SY5Y neurons where they did not modify neuronal death induced by a low concentration of rotenone (0.1 μM for 24 h), but significantly increased rotenone neurotoxicity when shed from CHPG-treated BV2 cells. miR146a was increased in CHPG-treated MVs, an effect concealed in MVs from LPS-activated BV2 cells that showed per se an increase in miRNA146a levels. The present data support a role for microglia-shed MVs in mGlu5-mediated modulation of neuronal death and identify miRNAs as potential critical mediators of this interaction. PMID:29170640

Host target modification as a strategy to counter pathogen hijacking of the jasmonate hormone receptor

DOE PAGES

Zhang, Li; Yao, Jian; Withers, John; ...

2015-11-02

In the past decade, characterization of the host targets of pathogen virulence factors took a center stage in the study of pathogenesis and disease susceptibility in plants and humans. However, the impressive knowledge of host targets has not been broadly exploited to inhibit pathogen infection. In this paper, we show that host target modification could be a promising new approach to “protect” the disease-vulnerable components of plants. In particular, recent studies have identified the plant hormone jasmonate (JA) receptor as one of the common targets of virulence factors from highly evolved biotrophic/hemibiotrophic pathogens. Strains of the bacterial pathogen Pseudomonas syringae,more » for example, produce proteinaceous effectors, as well as a JA-mimicking toxin, coronatine (COR), to activate JA signaling as a mechanism to promote disease susceptibility. Guided by the crystal structure of the JA receptor and evolutionary clues, we succeeded in modifying the JA receptor to allow for sufficient endogenous JA signaling but greatly reduced sensitivity to COR. Transgenic Arabidopsis expressing this modified receptor not only are fertile and maintain a high level of insect defense, but also gain the ability to resist COR-producing pathogens Pseudomonas syringae pv. tomato and P. syringae pv. maculicola. Finally, our results provide a proof-of-concept demonstration that host target modification can be a promising new approach to prevent the virulence action of highly evolved pathogens.« less

Targeting G protein-coupled receptor kinases (GRKs) in Heart Failure

PubMed Central

Brinks, Henriette; Koch, Walter J

2010-01-01

In the human body, over 1000 different G protein-coupled receptors (GPCRs) mediate a broad spectrum of extracellular signals at the plasma membrane, transmitting vital physiological features such as pain, sight, smell, inflammation, heart rate and contractility of muscle cells. Signaling through these receptors is primarily controlled and regulated by a group of kinases, the GPCR kinases (GRKs), of which only seven are known and thus, interference with these common downstream GPCR regulators suggests a powerful therapeutic strategy. Molecular modulation of the kinases that are ubiquitously expressed in the heart has proven GRK2, and also GRK5, to be promising targets for prevention and reversal of one of the most severe pathologies in man, chronic heart failure (HF). In this article we will focus on the structural aspects of these GRKs important for their physiological and pathological regulation as well as well known and novel therapeutic approaches that target these GRKs in order to overcome the development of cardiac injury and progression of HF. PMID:21218155

Decoy receptors block TRAIL sensitivity at a supracellular level: the role of stromal cells in controlling tumour TRAIL sensitivity.

PubMed

O'Leary, L; van der Sloot, A M; Reis, C R; Deegan, S; Ryan, A E; Dhami, S P S; Murillo, L S; Cool, R H; Correa de Sampaio, P; Thompson, K; Murphy, G; Quax, W J; Serrano, L; Samali, A; Szegezdi, E

2016-03-10

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand cytokine known for its cytotoxic activity against malignantly transformed cells. TRAIL induces cell death through binding to death receptors DR4 and DR5. The inhibitory decoy receptors (DcR1 and DcR2) co-expressed with death receptor 4 (DR4)/DR5 on the same cell can block the transmission of the apoptotic signal. Here, we show that DcRs also regulate TRAIL sensitivity at a supracellular level and thus represent a mechanism by which the microenvironment can diminish tumour TRAIL sensitivity. Mathematical modelling and layered or spheroid stroma-extracellular matrix-tumour cultures were used to model the tumour microenvironment. By engineering TRAIL to escape binding by DcRs, we found that DcRs do not only act in a cell-autonomous or cis-regulatory manner, but also exert trans-cellular regulation originating from stromal cells and affect tumour cells, highlighting the potent inhibitory effect of DcRs in the tumour tissue and the necessity of selective targeting of the two death-inducing TRAIL receptors to maximise efficacy.

Cannabinoid Receptor 2 Signaling in Neurodegenerative Disorders: From Pathogenesis to a Promising Therapeutic Target

PubMed Central

Cassano, Tommaso; Calcagnini, Silvio; Pace, Lorenzo; De Marco, Federico; Romano, Adele; Gaetani, Silvana

2017-01-01

As a consequence of an increasingly aging population, the number of people affected by neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, is rapidly increasing. Although the etiology of these diseases has not been completely defined, common molecular mechanisms including neuroinflammation, excitotoxicity and mitochondrial dysfunction have been confirmed and can be targeted therapeutically. Moreover, recent studies have shown that endogenous cannabinoid signaling plays a number of modulatory roles throughout the central nervous system (CNS), including the neuroinflammation and neurogenesis. In particular, the up-regulation of type-2 cannabinoid (CB2) receptors has been found in a number of neurodegenerative disorders. Thus, the modulation of CB2 receptor signaling may represent a promising therapeutic target with minimal psychotropic effects that can be used to modulate endocannabinoid-based therapeutic approaches and to reduce neuronal degeneration. For these reasons this review will focus on the CB2 receptor as a promising pharmacological target in a number of neurodegenerative diseases. PMID:28210207

Angiotensin II type 1 receptor blockade does not enhance apoptotic cell death during ischemia and reperfusion in humans in vivo.

PubMed

Meijer, Patrick; Wouters, Constantijn W; Oyen, Wim J; Boerman, Otto C; Scheffer, Gert Jan; Smits, Paul; Rongen, Gerard A

2011-06-01

Despite the theoretical benefits, angiotensin II type 1 receptor antagonists seem to enhance rather than reduce morbidity and mortality after myocardial infarction compared with angiotensin-converting enzyme inhibitors. This may result from unopposed angiotensin II type 2 receptor stimulation, which is associated with enhanced apoptotic cell death and increased infarct size. We studied whether the clinical effectiveness of irbesartan is hampered by enhanced apoptotic activity, detected by exposition of phosphatidylserines, during ischemia and reperfusion in humans in vivo. Twenty healthy male volunteers were randomized to a 1-week treatment with irbesartan (300 mg/d) or placebo in a double-blind fashion. After treatment, all participants underwent 10 minutes of ischemic exercise of the nondominant forearm. Upon reperfusion, Tc-99m-labeled Annexin A5 was administered, and 1 and 4 hours afterward, both hands were scanned using a gamma camera. Targeting of annexin A5, expressed as the percentage difference in radioactivity in the area of interest (thenar muscle) between experimental and control hand, did not differ between participants treated with irbesartan or placebo. Therefore, irbesartan does not enhance phosphatidylserine exposition in humans in vivo. The results of this study do not support enhanced apoptotic activity after treatment with irbesartan in a setting of ischemia and reperfusion.

Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

NASA Astrophysics Data System (ADS)

Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm; Iversen, Frank; Liu, Zhuo; Thomsen, Karen; Pedersen, Michael; Skrydstrup, Troels; Nielsen, Niels Chr.; Ploug, Michael; Kjems, Jørgen

2013-08-01

Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific

Death receptor 6 induces apoptosis not through type I or type II pathways, but via a unique mitochondria-dependent pathway by interacting with Bax protein.

PubMed

Zeng, Linlin; Li, Ting; Xu, Derek C; Liu, Jennifer; Mao, Guozhang; Cui, Mei-Zhen; Fu, Xueqi; Xu, Xuemin

2012-08-17

Cells undergo apoptosis through two major pathways, the extrinsic pathway (death receptor pathway) and the intrinsic pathway (the mitochondrial pathway). These two pathways can be linked by caspase-8-activated truncated Bid formation. Very recently, death receptor 6 (DR6) was shown to be involved in the neurodegeneration observed in Alzheimer disease. DR6, also known as TNFRSF21, is a relatively new member of the death receptor family, and it was found that DR6 induces apoptosis when it is overexpressed. However, how the death signal mediated by DR6 is transduced intracellularly is not known. To this end, we have examined the roles of caspases, apoptogenic mitochondrial factor cytochrome c, and the Bcl-2 family proteins in DR6-induced apoptosis. Our data demonstrated that Bax translocation is absolutely required for DR6-induced apoptosis. On the other hand, inhibition of caspase-8 and knockdown of Bid have no effect on DR6-induced apoptosis. Our results strongly suggest that DR6-induced apoptosis occurs through a new pathway that is different from the type I and type II pathways through interacting with Bax.

Receptor-Targeted Nipah Virus Glycoproteins Improve Cell-Type Selective Gene Delivery and Reveal a Preference for Membrane-Proximal Cell Attachment.

PubMed

Bender, Ruben R; Muth, Anke; Schneider, Irene C; Friedel, Thorsten; Hartmann, Jessica; Plückthun, Andreas; Maisner, Andrea; Buchholz, Christian J

2016-06-01

Receptor-targeted lentiviral vectors (LVs) can be an effective tool for selective transfer of genes into distinct cell types of choice. Moreover, they can be used to determine the molecular properties that cell surface proteins must fulfill to act as receptors for viral glycoproteins. Here we show that LVs pseudotyped with receptor-targeted Nipah virus (NiV) glycoproteins effectively enter into cells when they use cell surface proteins as receptors that bring them closely enough to the cell membrane (less than 100 Å distance). Then, they were flexible in receptor usage as demonstrated by successful targeting of EpCAM, CD20, and CD8, and as selective as LVs pseudotyped with receptor-targeted measles virus (MV) glycoproteins, the current standard for cell-type specific gene delivery. Remarkably, NiV-LVs could be produced at up to two orders of magnitude higher titers compared to their MV-based counterparts and were at least 10,000-fold less effectively neutralized than MV glycoprotein pseudotyped LVs by pooled human intravenous immunoglobulin. An important finding for NiV-LVs targeted to Her2/neu was an about 100-fold higher gene transfer activity when particles were targeted to membrane-proximal regions as compared to particles binding to a more membrane-distal epitope. Likewise, the low gene transfer activity mediated by NiV-LV particles bound to the membrane distal domains of CD117 or the glutamate receptor subunit 4 (GluA4) was substantially enhanced by reducing receptor size to below 100 Å. Overall, the data suggest that the NiV glycoproteins are optimally suited for cell-type specific gene delivery with LVs and, in addition, for the first time define which parts of a cell surface protein should be targeted to achieve optimal gene transfer rates with receptor-targeted LVs.

Targeting the adenosine 2A receptor enhances chimeric antigen receptor T cell efficacy

PubMed Central

Beavis, Paul A.; Henderson, Melissa A.; Giuffrida, Lauren; Mills, Jane K.; Sek, Kevin; Cross, Ryan S.; Davenport, Alexander J.; John, Liza B.; Mardiana, Sherly; Slaney, Clare Y.; Johnstone, Ricky W.; Trapani, Joseph A.; Stagg, John; Loi, Sherene; Kats, Lev; Gyorki, David; Kershaw, Michael H.; Darcy, Phillip K.

2017-01-01

Chimeric antigen receptor (CAR) T cells have been highly successful in treating hematological malignancies, including acute and chronic lymphoblastic leukemia. However, treatment of solid tumors using CAR T cells has been largely unsuccessful to date, partly because of tumor-induced immunosuppressive mechanisms, including adenosine production. Previous studies have shown that adenosine generated by tumor cells potently inhibits endogenous antitumor T cell responses through activation of adenosine 2A receptors (A2ARs). Herein, we have observed that CAR activation resulted in increased A2AR expression and suppression of both murine and human CAR T cells. This was reversible using either A2AR antagonists or genetic targeting of A2AR using shRNA. In 2 syngeneic HER2+ self-antigen tumor models, we found that either genetic or pharmacological targeting of the A2AR profoundly increased CAR T cell efficacy, particularly when combined with PD-1 blockade. Mechanistically, this was associated with increased cytokine production of CD8+ CAR T cells and increased activation of both CD8+ and CD4+ CAR T cells. Given the known clinical relevance of the CD73/adenosine pathway in several solid tumor types, and the initiation of phase I trials for A2AR antagonists in oncology, this approach has high translational potential to enhance CAR T cell efficacy in several cancer types. PMID:28165340

Targeting BCL-2 to enhance vulnerability to therapy in estrogen receptor-positive breast cancer.

PubMed

Merino, D; Lok, S W; Visvader, J E; Lindeman, G J

2016-04-14

The last three decades have seen significant progress in our understanding of the role of the pro-survival protein BCL-2 and its family members in apoptosis and cancer. BCL-2 and other pro-survival family members including Mcl-1 and BCL-XL have been shown to have a key role in keeping pro-apoptotic 'effector' proteins BAK and BAX in check. They also neutralize a group of 'sensor' proteins (such as BIM), which are triggered by cytotoxic stimuli such as chemotherapy. BCL-2 proteins therefore have a central role as guardians against apoptosis, helping cancer cells to evade cell death. More recently, an increasing number of BH3 mimetics, which bind and neutralize BCL-2 and/or its pro-survival relatives, have been developed. The utility of targeting BCL-2 in hematological malignancies has become evident in early-phase studies, with remarkable clinical responses seen in heavily pretreated patients. As BCL-2 is overexpressed in ~75% of breast cancer, there has been growing interest in determining whether this new class of drug could show similar promise in breast cancer. This review summarizes our current understanding of the role of BCL-2 and its family members in mammary gland development and breast cancer, recent progress in the development of new BH3 mimetics as well as their potential for targeting estrogen receptor-positive breast cancer.

Protease activated receptor-2 (PAR2): possible target of phytochemicals.

PubMed

Kakarala, Kavita Kumari; Jamil, Kaiser

2015-09-01

The use of phytochemicals either singly or in combination with other anticancer drugs comes with an advantage of less toxicity and minimal side effects. Signaling pathways play central role in cell cycle, cell growth, metabolism, etc. Thus, the identification of phytochemicals with promising antagonistic effect on the receptor/s playing key role in single transduction may have better therapeutic application. With this background, phytochemicals were screened against protease-activated receptor 2 (PAR2). PAR2 belongs to the superfamily of GPCRs and is an important target for breast cancer. Using in silico methods, this study was able to identify the phytochemicals with promising binding affinity suggesting their therapeutic potential in the treatment of breast cancer. The findings from this study acquires importance as the information on the possible agonists and antagonists of PAR2 is limited due its unique mechanism of activation.

Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

PubMed Central

Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

2015-01-01

Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

Photoreceptor cell death and rescue in retinal detachment and degenerations

PubMed Central

Murakami, Yusuke; Notomi, Shoji; Hisatomi, Toshio; Nakazawa, Toru; Ishibashi, Tatsuro; Miller, Joan W.; Vavvas, Demetrios G.

2013-01-01

Photoreceptor cell death is the ultimate cause of vision loss in various retinal disorders, including retinal detachment (RD). Photoreceptor cell death has been thought to occur mainly through apoptosis, which is the most characterized form of programmed cell death. The caspase family of cysteine proteases plays a central role for inducing apoptosis, and in experimental models of RD, dying photoreceptor cells exhibit caspase activation; however, there is a paradox that caspase inhibition alone does not provide a sufficient protection against photoreceptor cell loss, suggesting that other mechanisms of cell death are involved. Recent accumulating evidence demonstrates that non-apoptotic forms of cell death, such as autophagy and necrosis, are also regulated by specific molecular machinery, such as those mediated by autophagy-related proteins and receptor-interacting protein kinases, respectively. Here we summarize the current knowledge of cell death signaling and its roles in photoreceptor cell death after RD and other retinal degenerative diseases. A body of studies indicate that not only apoptotic but also autophagic and necrotic signaling are involved in photoreceptor cell death, and that combined targeting of these pathways may be an effective neuroprotective strategy for retinal diseases associated with photoreceptor cell loss. PMID:23994436

Drug addiction: targeting dynamic neuroimmune receptor interactions as a potential therapeutic strategy.

PubMed

Jacobsen, Jonathan Henry W; Hutchinson, Mark R; Mustafa, Sanam

2016-02-01

Drug addiction and dependence have proven to be difficult psychiatric disorders to treat. The limited efficacy of neuronally acting medications, such as acamprosate and naltrexone, highlights the need to identify novel targets. Recent research has underscored the importance of the neuroimmune system in many behavioural manifestations of drug addiction. In this review, we propose that our appreciation for complex phenotypes such as drug addiction and dependence will come with a greater understanding that these disorders are the result of intricate, interconnected signalling pathways that are, if only partially, determined at the receptor level. The idea of receptor heteromerisation and receptor mosaics will be introduced to explain cross talk between the receptors and signalling molecules implicated in neuroimmune signalling pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC-NLR proteins.

PubMed

Cesari, Stella; Moore, John; Chen, Chunhong; Webb, Daryl; Periyannan, Sambasivam; Mago, Rohit; Bernoux, Maud; Lagudah, Evans S; Dodds, Peter N

2016-09-06

Plants possess intracellular immune receptors designated "nucleotide-binding domain and leucine-rich repeat" (NLR) proteins that translate pathogen-specific recognition into disease-resistance signaling. The wheat immune receptors Sr33 and Sr50 belong to the class of coiled-coil (CC) NLRs. They confer resistance against a broad spectrum of field isolates of Puccinia graminis f. sp. tritici, including the Ug99 lineage, and are homologs of the barley powdery mildew-resistance protein MLA10. Here, we show that, similarly to MLA10, the Sr33 and Sr50 CC domains are sufficient to induce cell death in Nicotiana benthamiana Autoactive CC domains and full-length Sr33 and Sr50 proteins self-associate in planta In contrast, truncated CC domains equivalent in size to an MLA10 fragment for which a crystal structure was previously determined fail to induce cell death and do not self-associate. Mutations in the truncated region also abolish self-association and cell-death signaling. Analysis of Sr33 and Sr50 CC domains fused to YFP and either nuclear localization or nuclear export signals in N benthamiana showed that cell-death induction occurs in the cytosol. In stable transgenic wheat plants, full-length Sr33 proteins targeted to the cytosol provided rust resistance, whereas nuclear-targeted Sr33 was not functional. These data are consistent with CC-mediated induction of both cell-death signaling and stem rust resistance in the cytosolic compartment, whereas previous research had suggested that MLA10-mediated cell-death and disease resistance signaling occur independently, in the cytosol and nucleus, respectively.

Calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors trigger neuronal nitric-oxide synthase activation to promote nerve cell death in an Src kinase-dependent fashion.

PubMed

Socodato, Renato; Santiago, Felipe N; Portugal, Camila C; Domingues, Ana F; Santiago, Ana R; Relvas, João B; Ambrósio, António F; Paes-de-Carvalho, Roberto

2012-11-09

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-DL-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death.

Antitumor activity of cytotoxic T lymphocytes engineered to target vascular endothelial growth factor receptors

NASA Astrophysics Data System (ADS)

Niederman, Thomas M. J.; Ghogawala, Zoher; Carter, Bob S.; Tompkins, Hillary S.; Russell, Margaret M.; Mulligan, Richard C.

2002-05-01

The demonstration that angiogenesis is required for the growth of solid tumors has fueled an intense interest in the development of new therapeutic strategies that target the tumor vasculature. Here we report the development of an immune-based antiangiogenic strategy that is based on the generation of T lymphocytes that possess a killing specificity for cells expressing vascular endothelial growth factor receptors (VEGFRs). To target VEGFR-expressing cells, recombinant retroviral vectors were generated that encoded a chimeric T cell receptor comprised of VEGF sequences linked to intracellular signaling sequences derived from the chain of the T cell receptor. After transduction of primary murine CD8 lymphocytes by such vectors, the transduced cells were shown to possess an efficient killing specificity for cells expressing the VEGF receptor, Flk-1, as measured by in vitro cytotoxicity assays. After adoptive transfer into tumor-bearing mice, the genetically modified cytotoxic T lymphocytes strongly inhibited the growth of a variety of syngeneic murine tumors and human tumor xenografts. An increased effect on in vivo tumor growth inhibition was seen when this therapy was combined with the systemic administration of TNP-470, a conventional angiogenesis inhibitor. The utilization of the immune system to target angiogenic markers expressed on tumor vasculature may prove to be a powerful means for controlling tumor growth.

Epidermal Growth Factor Receptor targeting in non-small cell lung cancer: revisiting different strategies against the same target.

PubMed

Castañón, Eduardo; Martín, Patricia; Rolfo, Christian; Fusco, Juan P; Ceniceros, Lucía; Legaspi, Jairo; Santisteban, Marta; Gil-Bazo, Ignacio

2014-01-01

Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the paradigm of treatment in non-small cell lung cancer (NSCLC). The molecular biology study of EGFR has led to clinical trials that select patients more accurately, regarding the presence of EGFR activating mutations. Nonetheless, a lack of response or a temporary condition of the response has been detected in patients on EGFR TKIs. This has urged to study potential resistance mechanisms underneath. The most important ones are the presence of secondary mutations in EGFR, such as T790M, or the overexpression of mesenchymal-epithelial transition factor (MET) that may explain why patients who initially respond to EGFR TKIs, may ultimately become refractory. Several approaches have been taken and new drugs both targeting EGFR resistance-mutation or MET are currently being developed. Here we review and update the EGFR biological pathway as well as the clinical data leading to approval of the EGFR TKIs currently in the market. New compounds under investigation targeting resistance mutations or dually targeting EGFR and other relevant receptors are also reviewed and discussed.

Macrophage-mediated trogocytosis leads to death of antibody-opsonized tumor cells

PubMed Central

Velmurugan, Ramraj; Challa, Dilip K.; Ram, Sripad; Ober, Raimund J.; Ward, E. Sally

2016-01-01

Understanding the complex behavior of effector cells such as monocytes or macrophages in regulating cancerous growth is of central importance for cancer immunotherapy. Earlier studies using CD20-specific antibodies have demonstrated that the Fcγ receptor (FcγR)-mediated transfer of the targeted receptors from tumor cells to these effector cells through trogocytosis can enable escape from antibody therapy, leading to the viewpoint that this process is pro-tumorigenic. In the current study we demonstrate that persistent trogocytic attack results in the killing of HER2-overexpressing breast cancer cells. Further, antibody engineering to increase FcγR interactions enhances this tumoricidal activity. These studies extend the complex repertoire of activities of macrophages to trogocytic-mediated cell death of HER2-overexpressing target cells and have implications for the development of effective antibody-based therapies. PMID:27226489

Nuclear receptors in pancreatic tumor cells.

PubMed

Damaskos, Christos; Garmpis, Nikolaos; Karatzas, Theodore; Kostakis, Ioannis D; Nikolidakis, Lampros; Kostakis, Alkiviadis; Kouraklis, Gregory

2014-12-01

This review focuses on nuclear receptors expressed in pancreatic cancer. An extensive search of articles published up to March 2013 was conducted using the MEDLINE database. The key words used were "pancreatic cancer", "molecular receptors" and "growth factors". A total of 112 articles referred to pancreatic cancer, molecular receptors and/or growth factors were included. Receptors of growth factors, such as the epithelial growth factor receptor, insulin-like growth factor-1 receptor, vascular endothelial growth factor receptor and others, such as integrin α5β1, somatostatin receptors, the death receptor 5, claudin, notch receptors, mesothelin receptors, follicle-stimulating hormone receptors, the MUC1 receptor, the adrenomedullin receptor, the farnesoid X receptor, the transferrin receptor, sigma-2 receptors, the chemokine receptor CXCR4, the urokinase plasminogen activator receptor, the ephrine A2 receptor, the GRIA3 receptor, the RON receptor and the angiotensin II receptor AT-1 are expressed in pancreatic tumor cells. These molecules are implicated in tumor growth, apoptosis, angiogenesis, metastasis etc. After identifying the molecular receptors associated with the pancreatic cancer, many more target molecules playing important roles in tumor pathophysiology and senescence-associated signal transduction in cancer cells will be identified. This may have a significant influence on diagnosis, therapy and prognosis of pancreatic cancer. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

A plurality of molecular targets: The receptor ecosystem for bisphenol-A (BPA).

PubMed

MacKay, Harry; Abizaid, Alfonso

2018-05-01

Bisphenol-A (BPA) is a well-known endocrine disrupting compound (EDC), capable of affecting the normal function and development of the reproductive system, brain, adipose tissue, and more. In spite of these diverse and well characterized effects, there is often comparatively little known about the molecular mechanisms which bring them about. BPA has traditionally been regarded as a primarily estrogenic EDC, and this perspective is often what guides research into the effects of BPA. However, emerging data from in-vitro and in-silico models show that BPA binds with a significant number of hormone receptors, including a number of nuclear and membrane-bound estrogen receptors, androgen receptors, as well as the thyroid hormone receptor, glucocorticoid receptor, and PPARγ. With this increased diversity of receptor targets, it may be possible to explain some of the more puzzling aspects of BPA pharmacology, including its non-monotonic dose-response curve, as well as experimental results which disagree with estrogenic positive controls. This paper reviews the receptors for which BPA has a known interaction, and discusses the implications of taking these receptors into account when studying the disruptive effects of BPA on growth and development. Copyright © 2017 Elsevier Inc. All rights reserved.

[Targeting of membrane receptor tyrosine kinases: is there resistance in the HER?].

PubMed

Monnier, Lucile; Milano, Gérard; Penault-Llorca, Frédérique; Merlin, Jean-Louis

2004-09-01

Human Epidermal growth factor Receptors (HER) play an important role in cellular proliferation, and differentiation. Their overexpression in tumor tissues is often associated with a poor prognosis. Consequently, HER receptors are interesting therapeutic targets for cancer treatment. Two strategies are proposed. First, monoclonal antibodies can be used to inhibit the binding of one ligand to its receptor. The second approach is based upon the designing of tyrosine kinase inhibitors capable to bind into the phosphorylation site of the receptor. Consequently, both approaches block the signal transduction downstream. Resistance to anti receptor tyrosine kinase therapy can lead to enhanced morbidity associated with high therapeutic cost. Different mechanisms can be implicated. Non specific mechanisms include alterations of the signal transduction pathways (PI3K/AKT), recruitment of alternative receptor tyrosine kinase pathways (IGFR, VEGFR) and proteasome degradation inhibition. Other mechanisms are specific to HER and rely on inhibition of the binding of monoclonal antibodies (sialomucin-MUC4), heterodimerisation of HER, truncated soluble receptors intervention and mutated variants, as demonstrated very recently with EGF receptors, or genetic polymorphism. This paper reviews these different resistance mechanisms that have been identified in preclinical and clinical situations.

Therapeutic potential of targeting group III metabotropic glutamate receptors in the treatment of Parkinson's disease

PubMed Central

Duty, Susan

2010-01-01

Current drugs used in the treatment of Parkinson's disease (PD), for example, L-DOPA and dopamine agonists, are very effective at reversing the motor symptoms of the disease. However, they do little to combat the underlying degeneration of dopaminergic neurones in the substantia nigra pars compacta (SNc) and their long-term use is associated with the appearance of adverse effects such as L-DOPA-induced dyskinesia. Much emphasis has therefore been placed on finding alternative non-dopaminergic drugs that may circumvent some or all of these problems. Group III metabotropic glutamate (mGlu) receptors were first identified in the basal ganglia a decade ago. One or more of these receptors (mGlu4, mGlu7 or mGlu8) is found on pre-synaptic terminals of basal ganglia pathways whose overactivity is implicated not only in the generation of motor symptoms in PD, but also in driving the progressive SNc degeneration. The finding that drugs which activate group III mGlu receptors can inhibit transmission across these overactive synapses has lead to the proposal that group III mGlu receptors are promising targets for drug discovery in PD. This paper provides a comprehensive review of the role and target potential of group III mGlu receptors in the basal ganglia. Overwhelming evidence obtained from in vitro studies and animal models of PD supports group III mGlu receptors as potentially important drug targets for providing both symptom relief and neuroprotection in PD. PMID:20735415

Targeting the fibroblast growth factor receptors for the treatment of cancer.

PubMed

Lemieux, Steven M; Hadden, M Kyle

2013-06-01

Receptor tyrosine kinases (RTKs) are transmembrane proteins that play a critical role in stimulating signal transduction cascades to influence cell proliferation, growth, and differentiation and they have also been shown to promote angiogenesis when they are up-regulated or mutated. For this reason, their dysfunction has been implicated in the development of human cancer. Over the past decade, much attention has been devoted to developing inhibitors and antibodies against several classes of RTKs, including vascular endothelial growth factor receptors (VEGFRs), epidermal growth factor receptors (EGFRs), and platelet-derived growth factor receptors (PDGFRs). More recently, interest in the fibroblast growth factor receptor (FGFR) class of RTKs as a drug target for the treatment of cancer has emerged. Signaling through FGFRs is critical for normal cellular function and their dysregulation has been linked to various malignancies such as breast and prostate cancer. This review will focus on the current state of both small molecules and antibodies as FGFR inhibitors to provide insight into their development and future potential as anti-cancer agents.

Novel Dual Mitochondrial and CD44 Receptor Targeting Nanoparticles for Redox Stimuli-Triggered Release

NASA Astrophysics Data System (ADS)

Wang, Kaili; Qi, Mengjiao; Guo, Chunjing; Yu, Yueming; Wang, Bingjie; Fang, Lei; Liu, Mengna; Wang, Zhen; Fan, Xinxin; Chen, Daquan

2018-02-01

In this work, novel mitochondrial and CD44 receptor dual-targeting redox-sensitive multifunctional nanoparticles (micelles) based on oligomeric hyaluronic acid (oHA) were proposed. The amphiphilic nanocarrier was prepared by (5-carboxypentyl)triphenylphosphonium bromide (TPP), oligomeric hyaluronic acid (oHA), disulfide bond, and curcumin (Cur), named as TPP-oHA-S-S-Cur. The TPP targeted the mitochondria, the antitumor drug Cur served as a hydrophobic core, the CD44 receptor targeting oHA worked as a hydrophilic shell, and the disulfide bond acted as a connecting arm. The chemical structure of TPP-oHA-S-S-Cur was characterized by 1HNMR technology. Cur was loaded into the TPP-oHA-S-S-Cur micelles by self-assembly. Some properties, including the preparation of micelles, morphology, redox sensitivity, and mitochondrial targeting, were studied. The results showed that TPP-oHA-S-S-Cur micelles had a mean diameter of 122.4 ± 23.4 nm, zeta potential - 26.55 ± 4.99 mV. In vitro release study and cellular uptake test showed that TPP-oHA-S-S-Cur micelles had redox sensibility, dual targeting to mitochondrial and CD44 receptor. This work provided a promising smart multifunctional nanocarrier platform to enhance the solubility, decrease the side effects, and improve the therapeutic efficacy of anticancer drugs.

Modes of Action, Resistance and Toxicity of Insecticides Targeting Nicotinic Acetylcholine Receptors.

PubMed

Ihara, Makoto; Buckingham, Steven D; Matsuda, Kazuhiko; Sattelle, David B

2017-01-01

Nicotinic acetylcholine receptors (nAChRs) of insects play a key role in fast excitatory neurotransmission. Several classes of insecticides target insect nAChRs, which are composed of subunit members of a family of multiple subunit encoding genes. Alternative splicing and RNA A-to-I editing can add further to receptor diversity. Native and recombinant receptors have been explored as sites of insecticide action using radioligands, electrophysiology and site-directed mutagenesis. We have reviewed the properties of native and recombinant insect nAChRs, the challenges of functional recombinant insect nAChR expression, nAChR interactions with ligands acting at orthosteric and allosteric sites and in particular their interactions with insecticides. Actions on insect nAChRs of cartap, neonicotinoids, spinosyns, sulfoxamines, butenolides and mesoionic insecticides are reviewed and current knowledge of their modes of action are addressed. Mutations that add to our understanding of insecticide action and those leading to resistance are discussed. Co-crystallisation of neonicotinoids with the acetylcholine binding protein (AChBP), a surrogate for the nAChR ligand binding domain, has proved instructive. Toxicity issues relating to insecticides targeting nAChRs are also considered. An overview of insecticide classes targeting insect nAChRs has enhanced our understanding of these important receptors and their insecticide binding sites. However, the subunit composition of native nAChRs remains poorly understood and functional expression still presents difficulties. These topics together with improved understanding of the precise sites of insecticide actions on insect nAChRs will be the subject of future research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Structural Probing of Off-Target G Protein-Coupled Receptor Activities within a Series of Adenosine/Adenine Congeners

PubMed Central

Paoletta, Silvia; Tosh, Dilip K.; Salvemini, Daniela; Jacobson, Kenneth A.

2014-01-01

We studied patterns of off-target receptor interactions, mostly at G protein-coupled receptors (GPCRs) in the µM range, of nucleoside derivatives that are highly engineered for nM interaction with adenosine receptors (ARs). Because of the considerable interest of using AR ligands for treating diseases of the CNS, we used the Psychoactive Drug Screening Program (PDSP) for probing promiscuity of these adenosine/adenine congeners at 41 diverse receptors, channels and a transporter. The step-wise truncation of rigidified, trisubstituted (at N6, C2, and 5′ positions) nucleosides revealed unanticipated interactions mainly with biogenic amine receptors, such as adrenergic receptors and serotonergic receptors, with affinities as high as 61 nM. The unmasking of consistent sets of structure activity relationship (SAR) at novel sites suggested similarities between receptor families in molecular recognition. Extensive molecular modeling of the GPCRs affected suggested binding modes of the ligands that supported the patterns of SAR at individual receptors. In some cases, the ligand docking mode closely resembled AR binding and in other cases the ligand assumed different orientations. The recognition patterns for different GPCRs were clustered according to which substituent groups were tolerated and explained in light of the complementarity with the receptor binding site. Thus, some likely off-target interactions, a concern for secondary drug effects, can be predicted for analogues of this set of substructures, aiding the design of additional structural analogues that either eliminate or accentuate certain off-target activities. Moreover, similar analyses could be performed for unrelated structural families for other GPCRs. PMID:24859150

Structural probing of off-target G protein-coupled receptor activities within a series of adenosine/adenine congeners.

PubMed

Paoletta, Silvia; Tosh, Dilip K; Salvemini, Daniela; Jacobson, Kenneth A

2014-01-01

We studied patterns of off-target receptor interactions, mostly at G protein-coupled receptors (GPCRs) in the µM range, of nucleoside derivatives that are highly engineered for nM interaction with adenosine receptors (ARs). Because of the considerable interest of using AR ligands for treating diseases of the CNS, we used the Psychoactive Drug Screening Program (PDSP) for probing promiscuity of these adenosine/adenine congeners at 41 diverse receptors, channels and a transporter. The step-wise truncation of rigidified, trisubstituted (at N6, C2, and 5' positions) nucleosides revealed unanticipated interactions mainly with biogenic amine receptors, such as adrenergic receptors and serotonergic receptors, with affinities as high as 61 nM. The unmasking of consistent sets of structure activity relationship (SAR) at novel sites suggested similarities between receptor families in molecular recognition. Extensive molecular modeling of the GPCRs affected suggested binding modes of the ligands that supported the patterns of SAR at individual receptors. In some cases, the ligand docking mode closely resembled AR binding and in other cases the ligand assumed different orientations. The recognition patterns for different GPCRs were clustered according to which substituent groups were tolerated and explained in light of the complementarity with the receptor binding site. Thus, some likely off-target interactions, a concern for secondary drug effects, can be predicted for analogues of this set of substructures, aiding the design of additional structural analogues that either eliminate or accentuate certain off-target activities. Moreover, similar analyses could be performed for unrelated structural families for other GPCRs.

Designer interface peptide grafts target estrogen receptor alpha dimerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, S.; Asare, B.K.; Biswas, P.K., E-mail: pbiswas@tougaloo.edu

The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization.more » Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

Evolution of Olfactory Receptor Genes in Primates Dominated by Birth-and-Death Process

PubMed Central

Dong, Dong; He, Guimei; Zhang, Shuyi

2009-01-01

Olfactory receptor (OR) is a large family of G protein–coupled receptors that can detect odorant in order to generate the sense of smell. They constitute one of the largest multiple gene families in animals including primates. To better understand the variation in odor perception and evolution of OR genes among primates, we computationally identified OR gene repertoires in orangutans, marmosets, and mouse lemurs and investigated the birth-and-death process of OR genes in the primate lineage. The results showed that 1) all the primate species studied have no more than 400 intact OR genes, fewer than rodents and canine; 2) Despite the similar number of OR genes in the genome, the makeup of the OR gene repertoires between different primate species is quite different as they had undergone dramatic birth-and-death evolution with extensive gene losses in the lineages leading to current species; 3) Apes and Old World monkey (OWM) have similar fraction of pseudogenes, whereas New World monkey (NWM) have fewer pseudogenes. To measure the selective pressure that had affected the OR gene repertoires in primates, we compared the ratio of nonsynonymous with synonymous substitution rates by using 70 one-to-one orthologous quintets among five primate species. We found that OR genes showed relaxed selective constraints in apes (humans, chimpanzees, and orangutans) than in OWMs (macaques) and NWMs (marmosets). We concluded that OR gene repertoires in primates have evolved in such a way to adapt to their respective living environments. Differential selective constraints might play important role in the primate OR gene evolution in each primate species. PMID:20333195

The intracellular carboxyl tail of the PAR-2 receptor controls intracellular signaling and cell death.

PubMed

Zhu, Zhihui; Stricker, Rolf; Li, Rong yu; Zündorf, Gregor; Reiser, Georg

2015-03-01

The protease-activated receptors are a group of unique G protein-coupled receptors, including PAR-1, PAR-2, PAR-3 and PAR-4. PAR-2 is activated by multiple trypsin-like serine proteases, including trypsin, tryptase and coagulation proteases. The clusters of phosphorylation sites in the PAR-2 carboxyl tail are suggested to be important for the binding of adaptor proteins to initiate intracellular signaling to Ca(2+) and mitogen-activated protein kinases. To explore the functional role of PAR-2 carboxyl tail in controlling intracellular Ca(2+), ERK and AKT signaling, a series of truncated mutants containing different clusters of serines/threonines were generated and expressed in HEK293 cells. Firstly, we observed that lack of the complete C-terminus of PAR-2 in a mutated receptor gave a relatively low level of localization on the cell plasma membrane. Secondly, the shortened carboxyl tail containing 13 amino acids was sufficient for receptor internalization. Thirdly, the cells expressing truncation mutants showed deficits in their capacity to couple to intracellular Ca(2+) and ERK and AKT signaling upon trypsin challenge. In addition, HEK293 cells carrying different PAR-2 truncation mutants displayed decreased levels of cell survival after long-lasting trypsin stimulation. In summary, the PAR-2 carboxyl tail was found to control the receptor localization, internalization, intracellular Ca(2+) responses and signaling to ERK and AKT. The latter can be considered to be important for cell death control.

Exploiting cancer’s phenotypic guise against itself: targeting ectopically expressed peptide G-protein coupled receptors for lung cancer therapy

PubMed Central

Khan, Mahjabin; Huang, Tao; Lin, Cheng-Yuan; Wu, Jiang; Fan, Bao-Min; Bian, Zhao-Xiang

2017-01-01

Lung cancer, claiming millions of lives annually, has the highest mortality rate worldwide. This advocates the development of novel cancer therapies that are highly toxic for cancer cells but negligibly toxic for healthy cells. One of the effective treatments is targeting overexpressed surface receptors of cancer cells with receptor-specific drugs. The receptors-in-focus in the current review are the G-protein coupled receptors (GPCRs), which are often overexpressed in various types of tumors. The peptide subfamily of GPCRs is the pivot of the current article owing to the high affinity and specificity to and of their cognate peptide ligands, and the proven efficacy of peptide-based therapeutics. The article summarizes various ectopically expressed peptide GPCRs in lung cancer, namely, Cholecystokinin-B/Gastrin receptor, the Bombesin receptor family, Bradykinin B1 and B2 receptors, Arginine vasopressin receptors 1a, 1b and 2, and the Somatostatin receptor type 2. The autocrine growth and pro-proliferative pathways they mediate, and the distinct tumor-inhibitory effects of somatostatin receptors are then discussed. The next section covers how these pathways may be influenced or ‘corrected’ through therapeutics (involving agonists and antagonists) targeting the overexpressed peptide GPCRs. The review proceeds on to Nano-scaled delivery platforms, which enclose chemotherapeutic agents and are decorated with peptide ligands on their external surface, as an effective means of targeting cancer cells. We conclude that targeting these overexpressed peptide GPCRs is potentially evolving as a highly promising form of lung cancer therapy. PMID:29262666

Early clinical development of epidermal growth factor receptor targeted therapy in breast cancer.

PubMed

Matsuda, Naoko; Lim, Bora; Wang, Xiaoping; Ueno, Naoto T

2017-04-01

Epidermal growth factor receptor (EGFR) targeted treatment has been evaluated but has not shown a clear clinical benefit for breast cancer. This review article aims to consider the knowledge of the biological background of EGFR pathways in dissecting clinical studies of EGFR targeted treatment in breast cancer. Areas covered: This review focuses on the role of the EGFR pathway and the investigational drugs that target EGFR for breast cancer. Expert opinion: Recent studies have indicated that EGFR targeted therapy for breast cancer has some promising effects for patients with triple-negative breast cancer, basal-like breast cancer, and inflammatory breast cancer. However, predictive and prognostic biomarkers for EGFR targeted therapy have not been identified. The overexpression or amplification of EGFR itself may not be the true factor of induction of the canonical pathway as an oncogenic driver of breast cancer. Instead, downstream, non-canonical pathways related to EGFR may contribute to some aspects of the biological behavior of breast cancer; therefore, the blockade of the receptor could result in sufficient suppression of downstream pathways to inhibit the aggressive behavior of breast cancer. Mechanistic studies to investigate the dynamic interaction between the EGFR pathway and non-canonical pathways are warranted.

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water

PubMed Central

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury. PMID:26316710

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water.

PubMed

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury.

Targeting the androgen receptor in triple-negative breast cancer: current perspectives.

PubMed

Mina, Alain; Yoder, Rachel; Sharma, Priyanka

2017-01-01

Triple-negative breast cancer (TNBC) is an aggressive subtype associated with frequent recurrence and metastasis. Unlike hormone receptor-positive subtypes, treatment of TNBC is currently limited by the lack of clinically available targeted therapies. Androgen signaling is necessary for normal breast development, and its dysregulation has been implicated in breast tumorigenesis. In recent years, gene expression studies have identified a subset of TNBC that is enriched for androgen receptor (AR) signaling. Interference with androgen signaling in TNBC is promising, and AR-inhibiting drugs have shown antitumorigenic activity in preclinical and proof of concept clinical studies. Recent advances in our understanding of androgenic signaling in TNBC, along with the identification of interacting pathways, are allowing development of the next generation of clinical trials with AR inhibitors. As novel AR-targeting agents are developed and evaluated in clinical trials, it is equally important to establish a robust set of biomarkers for identification of TNBC tumors that are most likely to respond to AR inhibition.

Simultaneous induction of apoptotic, autophagic, and necrosis-like cell death by monoclonal antibodies recognizing chicken transferrin receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohno, Yoshiya; Yagi, Hideki; Nakamura, Masanori

Programmed cell death (PCD) is categorized as apoptotic, autophagic, or necrosis-like. Although the possibility that plural (two or three) death signals could be induced by a given stimulus has been reported, the precise mechanisms regulating PCD are not well understood. Recently, we have obtained two anti-chicken transferrin receptor (TfR) monoclonal antibodies (mAbs; D18 and D19) inducing a unique cell death. Although the cell death had several features of apoptosis, autophagic and necrosis-like morphological alterations were simultaneously observed in electron microphotographs. In addition to cells with condensed chromatin and an intact plasma membrane (apoptotic cells), cells having many vacuoles in themore » cytoplasm (autophagic cells), and enlarged cells with ruptured plasma membranes (necrosis-like cells) were observed in DT40 cells treated with the mAbs, however, the latter two types of dead cells were not detected upon treatment with staurosporine, a typical apoptosis inducer. In autophagic cells, numerous membrane-bound vesicles occupying most of the cytoplasmic space, which frequently contained electron-dense materials from cytoplasmic fragments and organelles, were observed. The simultaneous induction of multiple death signals from a stimulus via the TfR is of great interest to those researching cell death. In addition, activation of caspases was observed in DT40 cells treated with D19, however, the cell death was not inhibited with z-VAD-fmk, a pan-caspase inhibitor, suggesting that at least in part, a caspase-independent pathway is involved in the TfR-mediated cell death.« less

Targeting the interleukin-11 receptor α in metastatic prostate cancer: A first-in-man study.

PubMed

Pasqualini, Renata; Millikan, Randall E; Christianson, Dawn R; Cardó-Vila, Marina; Driessen, Wouter H P; Giordano, Ricardo J; Hajitou, Amin; Hoang, Anh G; Wen, Sijin; Barnhart, Kirstin F; Baze, Wallace B; Marcott, Valerie D; Hawke, David H; Do, Kim-Anh; Navone, Nora M; Efstathiou, Eleni; Troncoso, Patricia; Lobb, Roy R; Logothetis, Christopher J; Arap, Wadih

2015-07-15

Receptors in tumor blood vessels are attractive targets for ligand-directed drug discovery and development. The authors have worked systematically to map human endothelial receptors ("vascular zip codes") within tumors through direct peptide library selection in cancer patients. Previously, they selected a ligand-binding motif to the interleukin-11 receptor alpha (IL-11Rα) in the human vasculature. The authors generated a ligand-directed, peptidomimetic drug (bone metastasis-targeting peptidomimetic-11 [BMTP-11]) for IL-11Rα-based human tumor vascular targeting. Preclinical studies (efficacy/toxicity) included evaluating BMTP-11 in prostate cancer xenograft models, drug localization, targeted apoptotic effects, pharmacokinetic/pharmacodynamic analyses, and dose-range determination, including formal (good laboratory practice) toxicity across rodent and nonhuman primate species. The initial BMTP-11 clinical development also is reported based on a single-institution, open-label, first-in-class, first-in-man trial (National Clinical Trials number NCT00872157) in patients with metastatic, castrate-resistant prostate cancer. BMTP-11 was preclinically promising and, thus, was chosen for clinical development in patients. Limited numbers of patients who had castrate-resistant prostate cancer with osteoblastic bone metastases were enrolled into a phase 0 trial with biology-driven endpoints. The authors demonstrated biopsy-verified localization of BMTP-11 to tumors in the bone marrow and drug-induced apoptosis in all patients. Moreover, the maximum tolerated dose was identified on a weekly schedule (20-30 mg/m(2) ). Finally, a renal dose-limiting toxicity was determined, namely, dose-dependent, reversible nephrotoxicity with proteinuria and casts involving increased serum creatinine. These biologic endpoints establish BMTP-11 as a targeted drug candidate in metastatic, castrate-resistant prostate cancer. Within a larger discovery context, the current findings indicate that

Targeting the interleukin-11 receptor α in metastatic prostate cancer: A first-in-man study

PubMed Central

Pasqualini, Renata; Millikan, Randall E; Christianson, Dawn R; Cardó-Vila, Marina; Driessen, Wouter H P; Giordano, Ricardo J; Hajitou, Amin; Hoang, Anh G; Wen, Sijin; Barnhart, Kirstin F; Baze, Wallace B; Marcott, Valerie D; Hawke, David H; Do, Kim-Anh; Navone, Nora M; Efstathiou, Eleni; Troncoso, Patricia; Lobb, Roy R; Logothetis, Christopher J; Arap, Wadih

2015-01-01

BACKGROUND Receptors in tumor blood vessels are attractive targets for ligand-directed drug discovery and development. The authors have worked systematically to map human endothelial receptors (“vascular zip codes”) within tumors through direct peptide library selection in cancer patients. Previously, they selected a ligand-binding motif to the interleukin-11 receptor alpha (IL-11Rα) in the human vasculature. METHODS The authors generated a ligand-directed, peptidomimetic drug (bone metastasis-targeting peptidomimetic-11 [BMTP-11]) for IL-11Rα–based human tumor vascular targeting. Preclinical studies (efficacy/toxicity) included evaluating BMTP-11 in prostate cancer xenograft models, drug localization, targeted apoptotic effects, pharmacokinetic/pharmacodynamic analyses, and dose-range determination, including formal (good laboratory practice) toxicity across rodent and nonhuman primate species. The initial BMTP-11 clinical development also is reported based on a single-institution, open-label, first-in-class, first-in-man trial (National Clinical Trials number NCT00872157) in patients with metastatic, castrate-resistant prostate cancer. RESULTS BMTP-11 was preclinically promising and, thus, was chosen for clinical development in patients. Limited numbers of patients who had castrate-resistant prostate cancer with osteoblastic bone metastases were enrolled into a phase 0 trial with biology-driven endpoints. The authors demonstrated biopsy-verified localization of BMTP-11 to tumors in the bone marrow and drug-induced apoptosis in all patients. Moreover, the maximum tolerated dose was identified on a weekly schedule (20-30 mg/m2). Finally, a renal dose-limiting toxicity was determined, namely, dose-dependent, reversible nephrotoxicity with proteinuria and casts involving increased serum creatinine. CONCLUSIONS These biologic endpoints establish BMTP-11 as a targeted drug candidate in metastatic, castrate-resistant prostate cancer. Within a larger discovery

Breast Cancer: Current Molecular Therapeutic Targets and New Players.

PubMed

Nagini, Siddavaram

2017-01-01

Breast cancer is the most common cancer and the most frequent cause of cancer death among women worldwide. Breast cancer is a complex, heterogeneous disease classified into hormone-receptor-positive, human epidermal growth factor receptor-2 overexpressing (HER2+) and triple-negative breast cancer (TNBC) based on histological features. Endocrine therapy, the mainstay of treatment for hormone-responsive breast cancer involves use of selective estrogen receptor modulators (SERMs), selective estrogen receptor downregulators (SERDs) and aromatase inhibitors (AIs). Agents that target estrogen receptor (ER) and HER2 such as tamoxifen and trastuzumab have been the most extensively used therapeutics for breast cancer. Crosstalk between ER and other signalling networks as well as epigenetic mechanisms have been envisaged to contribute to endocrine therapy resistance. TNBC, a complex, heterogeneous, aggressive form of breast cancer in which the cells do not express ER, progesterone receptor or HER2 is refractory to therapy. Several molecular targets are being explored to target TNBC including androgen receptor, epidermal growth factor receptor (EGFR), poly(ADP-ribose) polymerase (PARP), and vascular endothelial growth factor (VEGF). Receptors, protein tyrosine kinases, phosphatases, proteases, PI3K/Akt signalling pathway, microRNAs (miRs) and long noncoding RNAs (lncRNAs) are potential therapeutic targets. miR-based therapeutic approaches include inhibition of oncomiRs by antisense oligonucleotides, restoration of tumour suppressors using miR mimics, and chemical modification of miRs. The lnRNAs HOTAIR, SPRY4-IT1, GAS5, and PANDAR, new players in tumour development and prognosis may have theranostic applications in breast cancer. Several novel classes of mechanism-based drugs have been designed and synthesised for treatment of breast cancer. Integration of nucleic acid sequencing studies with mass spectrometry-based peptide sequencing and posttranslational modifications as

TRPV2 activation induces apoptotic cell death in human T24 bladder cancer cells: a potential therapeutic target for bladder cancer.

PubMed

Yamada, Takahiro; Ueda, Takashi; Shibata, Yasuhiro; Ikegami, Yosuke; Saito, Masaki; Ishida, Yusuke; Ugawa, Shinya; Kohri, Kenjiro; Shimada, Shoichi

2010-08-01

To investigate the functional expression of the transient receptor potential vanilloid 2 (TRPV2) channel protein in human urothelial carcinoma (UC) cells and to determine whether calcium influx into UC cells through TRPV2 is involved in apoptotic cell death. The expression of TRPV2 mRNA in bladder cancer cell lines (T24, a poorly differentiated UC cell line and RT4, a well-differentiated UC cell line) was analyzed using reverse transcriptase-polymerase chain reaction. The calcium permeability of TRPV2 channels in T24 cells was investigated using a calcium imaging assay that used cannabidiol (CBD), a relatively selective TRPV2 agonist, and ruthenium red (RuR), a nonselective TRPV channel antagonist. The death of T24 or RT4 cells in the presence of CBD was evaluated using a cellular viability assay. Apoptosis of T24 cells caused by CBD was confirmed using an annexin-V assay and small interfering RNA (siRNA) silencing of TRPV2. TRPV2 mRNA was abundantly expressed in T24 cells. The expression level in UC cells was correlated with high-grade disease. The administration of CBD increased intracellular calcium concentrations in T24 cells. In addition, the viability of T24 cells progressively decreased with increasing concentrations of CBD, whereas RT4 cells were mostly unaffected. Cell death occurred via apoptosis caused by continuous influx of calcium through TRPV2. TRPV2 channels in UC cells are calcium-permeable and the regulation of calcium influx through these channels leads directly to the death of UC cells. TRPV2 channels in UC cells may be a potential new therapeutic target, especially in higher-grade UC cells. Copyright 2010 Elsevier Inc. All rights reserved.

Pathophysiological roles of P2 receptors in glial cells.

PubMed

Abbracchio, Maria P; Verderio, Claudia

2006-01-01

Extracellular nucleotides act through specific receptors on target cells: the seven ionotropic P2X and the eight G protein-coupled P2Y receptors. All these receptors are expressed by brain astroglia and microglia. In astrocytes, P2 receptors have been implicated in short-term calcium-dependent cell-cell communication. Upon mechanical stimulation or activation by other transmitters, astrocytes release ATP and respond to ATP with a propagating wave of intracellular calcium increases, allowing a homotypic astrocyte-astrocyte communication, as well as an heterotypic signalling which also involves neurons, oligodendrocytes and microglia. Astrocytic P2 receptors also mediate reactive astrogliosis, a reaction contributing to neuronal death in neurodegenerative diseases. Signalling leading to inflammatory astrogliosis involves induction of cyclo-oxygenase 2 through stimulation of ERK1,2 and of the transcriptional factors AP-1 and NF-kappaB. Microglia also express several P2 receptors linked to intracellular calcium increases. P2 receptor subtypes are differentially regulated by typical proinflammatory signals for these cells (e.g. lipopolysaccharide), suggesting specific roles in brain immune responses. Globally, these findings highlight the roles of P2 receptors in glial cell pathophysiology suggesting a contribution to neurodegenerative diseases characterized by excessive gliosis and neuro-inflammation. They also open up the possibility of modulating brain damage by ligands selectively targeting the specific P2 receptor subtypes involved in the gliotic response.

Intracellular cholesterol level regulates sensitivity of glioblastoma cells against temozolomide-induced cell death by modulation of caspase-8 activation via death receptor 5-accumulation and activation in the plasma membrane lipid raft.

PubMed

Yamamoto, Yutaro; Tomiyama, Arata; Sasaki, Nobuyoshi; Yamaguchi, Hideki; Shirakihara, Takuya; Nakashima, Katsuhiko; Kumagai, Kosuke; Takeuchi, Satoru; Toyooka, Terushige; Otani, Naoki; Wada, Kojiro; Narita, Yoshitaka; Ichimura, Koichi; Sakai, Ryuichi; Namba, Hiroki; Mori, Kentaro

2018-01-01

Development of resistance against temozolomide (TMZ) in glioblastoma (GBM) after continuous treatment with TMZ is one of the critical problems in clinical GBM therapy. Intracellular cholesterol regulates cancer cell biology, but whether intracellular cholesterol is involved in TMZ resistance of GBM cells remains unclear. The involvement of intracellular cholesterol in acquired resistance against TMZ in GBM cells was investigated. Intracellular cholesterol levels were measured in human U251 MG cells with acquired TMZ resistance (U251-R cells) and TMZ-sensitive control U251 MG cells (U251-Con cells), and found that the intracellular cholesterol level was significantly lower in U251-R cells than in U251-Con cells. In addition, treatment by intracellular cholesterol remover, methyl-beta cyclodextrin (MβCD), or intracellular cholesterol inducer, soluble cholesterol (Chol), regulated TMZ-induced U251-Con cell death in line with changes in intracellular cholesterol level. Involvement of death receptor 5 (DR5), a death receptor localized in the plasma membrane, was evaluated. TMZ without or with MβCD and/or Chol caused accumulation of DR5 into the plasma membrane lipid raft and formed a complex with caspase-8, an extrinsic caspase cascade inducer, reflected in the induction of cell death. In addition, treatment with caspase-8 inhibitor or knockdown of DR5 dramatically suppressed U251-Con cell death induced by combination treatment with TMZ, MβCD, and Chol. Combined treatment of Chol with TMZ reversed the TMZ resistance of U251-R cells and another GBM cell model with acquired TMZ resistance, whereas clinical antihypercholesterolemia agents at physiological concentrations suppressed TMZ-induced cell death of U251-Con cells. These findings suggest that intracellular cholesterol level affects TMZ treatment of GBM mediated via a DR5-caspase-8 mechanism. Copyright © 2017 Elsevier Inc. All rights reserved.

Targeted Delivery of Proteasome Inhibitors to Somatostatin-Receptor-Expressing Cancer Cells by Octreotide Conjugation.

PubMed

Beck, Philipp; Cui, Haissi; Hegemann, Julian D; Marahiel, Mohammed A; Krüger, Achim; Groll, Michael

2015-12-01

Clinical application of proteasome inhibitors (PIs) is so far limited to peripheral blood cancers due to the pronounced cytotoxicity towards all cell types. Targeted delivery of PIs could permit the treatment of other cancers along with decreasing side effects. Herein we describe the first small-molecule proteasome inhibitor conjugate for targeted delivery, created by fusing PIs to a synthetic ligand of somatostatin receptors, which are highly expressed in a variety of tumors. X-ray crystallographic studies and in vitro IC50 measurements demonstrated that addition of the cyclopeptide octreotide as a targeting vehicle does not affect the PI's binding mode. The cytotoxicity of the conjugate against somatostatin-receptor-expressing cells was up to 11-fold higher than that of a non-targeting surrogate. We have therefore established PIs as a new payload for drug conjugates and have shown that targeted delivery thereof could be a promising approach for the broader application of this FDA-approved class of compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Calcium-permeable α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors Trigger Neuronal Nitric-oxide Synthase Activation to Promote Nerve Cell Death in an Src Kinase-dependent Fashion*

PubMed Central

Socodato, Renato; Santiago, Felipe N.; Portugal, Camila C.; Domingues, Ana F.; Santiago, Ana R.; Relvas, João B.; Ambrósio, António F.; Paes-de-Carvalho, Roberto

2012-01-01

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2′,7′-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-dl-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death. PMID:22992730

Lysosomal membrane permeabilization is an early event in Sigma-2 receptor ligand mediated cell death in pancreatic cancer.

PubMed

Hornick, John R; Vangveravong, Suwanna; Spitzer, Dirk; Abate, Carmen; Berardi, Francesco; Goedegebuure, Peter; Mach, Robert H; Hawkins, William G

2012-05-02

Sigma-2 receptor ligands have been studied for treatment of pancreatic cancer because they are preferentially internalized by proliferating cells and induce apoptosis. This mechanism of apoptosis is poorly understood, with varying reports of caspase-3 dependence. We evaluated multiple sigma-2 receptor ligands in this study, each shown to decrease tumor burden in preclinical models of human pancreatic cancer. Fluorescently labeled sigma-2 receptor ligands of two classes (derivatives of SW43 and PB282) localize to cell membrane components in Bxpc3 and Aspc1 pancreatic cancer cells and accumulate in lysosomes. We found that interactions in the lysosome are critical for cell death following sigma-2 ligand treatment because selective inhibition of a protective lysosomal membrane glycoprotein, LAMP1, with shRNA greatly reduced the viability of cells following treatment. Sigma-2 ligands induced lysosomal membrane permeabilization (LMP) and protease translocation triggering downstream effectors of apoptosis. Subsequently, cellular oxidative stress was greatly increased following treatment with SW43, and the hydrophilic antioxidant N-acetylcysteine (NAC) gave greater protection against this than a lipophilic antioxidant, α-tocopherol (α-toco). Conversely, PB282-mediated cytotoxicity relied less on cellular oxidation, even though α-toco did provide protection from this ligand. In addition, we found that caspase-3 induction was not as significantly inhibited by cathepsin inhibitors as by antioxidants. Both NAC and α-toco protected against caspase-3 induction following PB282 treatment, while only NAC offered protection following SW43 treatment. The caspase-3 inhibitor DEVD-FMK offered significant protection from PB282, but not SW43. Sigma-2 ligand SW43 commits pancreatic cancer cells to death by a caspase-independent process involving LMP and oxidative stress which is protected from by NAC. PB282 however undergoes a caspase-dependent death following LMP protected by DEVD

Tyrosine dephosphorylation enhances the therapeutic target activity of epidermal growth factor receptor (EGFR) by disrupting its interaction with estrogen receptor (ER).

PubMed

Ma, Shao; Yin, Ning; Qi, Xiaomei; Pfister, Sandra L; Zhang, Mei-Jie; Ma, Rong; Chen, Guan

2015-05-30

Protein-protein interactions can increase or decrease its therapeutic target activity and the determining factors involved, however, are largely unknown. Here, we report that tyrosine-dephosphorylation of epidermal growth factor receptor (EGFR) increases its therapeutic target activity by disrupting its interaction with estrogen receptor (ER). Protein tyrosine phosphatase H1 (PTPH1) dephosphorylates the tyrosine kinase EGFR, disrupts its interaction with the nuclear receptor ER, and increases breast cancer sensitivity to small molecule tyrosine kinase inhibitors (TKIs). These effects require PTPH1 catalytic activity and its interaction with EGFR, suggesting that the phosphatase may increase the sensitivity by dephosphorylating EGFR leading to its dissociation with ER. Consistent with this notion, a nuclear-localization defective ER has a higher EGFR-binding activity and confers the resistance to TKI-induced growth inhibition. Additional analysis show that PTPH1 stabilizes EGFR, stimulates the membranous EGFR accumulation, and enhances the growth-inhibitory activity of a combination therapy of TKIs with an anti-estrogen. Since EGFR and ER both are substrates for PTPH1 in vitro and in intact cells, these results indicate that an inhibitory EGFR-ER protein complex can be switched off through a competitive enzyme-substrate binding. Our results would have important implications for the treatment of breast cancer with targeted therapeutics.

Sodium modulates opioid receptors through a membrane component different from G-proteins. Demonstration by target size analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ott, S.; Costa, T.; Herz, A.

1988-07-25

The target size for opioid receptor binding was studied after manipulations known to affect the interactions between receptor and GTP-binding regulatory proteins (G-proteins). Addition of GTP or its analogs to the binding reaction, exposure of intact cells to pertussis toxin prior to irradiation, or treatment of irradiated membranes with N-ethylmaleimide did not change the target size (approximately equal to 100 kDa) for opioid receptors in NG 108-15 cells and rat brain. These data suggest that the 100-kDa species does not include an active subunit of a G-protein or alternatively that GTP does not promote the dissociation of the receptor-G-protein complex.more » The presence of Na+ (100 mM) in the radioligand binding assay induced a biphasic decay curve for agonist binding and a flattening of the monoexponential decay curve for a partial agonist. In both cases the effect was explained by an irradiation-induced loss of the low affinity state of the opioid receptor produced by the addition of Na+. This suggests that an allosteric inhibitor that mediates the effect of sodium on the receptor is destroyed at low doses of irradiation, leaving receptors which are no longer regulated by sodium. The effect of Na+ on target size was slightly increased by the simultaneous addition of GTP but was not altered by pertussis toxin treatment. Thus, the sodium unit is distinct from G-proteins and may represent a new component of the opioid receptor complex. Assuming a simple bimolecular model of one Na+ unit/receptor, the size of this inhibitor can be measured as 168 kDa.« less

Targeting c-KIT (CD117) by dasatinib and radotinib promotes acute myeloid leukemia cell death.

PubMed

Heo, Sook-Kyoung; Noh, Eui-Kyu; Kim, Jeong Yi; Jeong, Yoo Kyung; Jo, Jae-Cheol; Choi, Yunsuk; Koh, SuJin; Baek, Jin Ho; Min, Young Joo; Kim, Hawk

2017-11-10

Dasatinib and radotinib are oral BCR-ABL tyrosine kinase inhibitors that were developed as drugs for the treatment of chronic myeloid leukemia. We report here that the c-KIT (CD117) targeting with dasatinib and radotinib promotes acute myeloid leukemia (AML) cell death, and c-KIT endocytosis is essential for triggering c-KIT-positive AML cell death by dasatinib and radotinib during the early stages. In addition, dasatinib and radotinib reduce heat shock protein 90β (HSP90β) expression and release Apaf-1 in c-KIT-positive AML cells. Finally, this activates a caspase-dependent apoptotic pathway in c-KIT-positive AML cells. Moreover, the inhibition of c-KIT endocytosis by dynamin inhibitor (DY) reversed cell viability and c-KIT expression by dasatinib and radotinib. HSP90β expression was recovered by DY in c-KIT-positive AML cells as well. Furthermore, the effect of radotinib on c-KIT and HSP90β showed the same pattern in a xenograft animal model using HEL92.1.7 cells. Therefore, dasatinib and radotinib promote AML cell death by targeting c-KIT. Taken together, these results indicate that dasatinib and radotinib treatment have a potential role in anti-leukemic therapy on c-KIT-positive AML cells.

Computational design of trimeric influenza-neutralizing proteins targeting the hemagglutinin receptor binding site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strauch, Eva-Maria; Bernard, Steffen M.; La, David

Many viral surface glycoproteins and cell surface receptors are homo-oligomers1, 2, 3, 4, and thus can potentially be targeted by geometrically matched homo-oligomers that engage all subunits simultaneously to attain high avidity and/or lock subunits together. The adaptive immune system cannot generally employ this strategy since the individual antibody binding sites are not arranged with appropriate geometry to simultaneously engage multiple sites in a single target homo-oligomer. We describe a general strategy for the computational design of homo-oligomeric protein assemblies with binding functionality precisely matched to homo-oligomeric target sites5, 6, 7, 8. In the first step, a small protein ismore » designed that binds a single site on the target. In the second step, the designed protein is assembled into a homo-oligomer such that the designed binding sites are aligned with the target sites. We use this approach to design high-avidity trimeric proteins that bind influenza A hemagglutinin (HA) at its conserved receptor binding site. The designed trimers can both capture and detect HA in a paper-based diagnostic format, neutralizes influenza in cell culture, and completely protects mice when given as a single dose 24 h before or after challenge with influenza.« less

Early clinical development of epidermal growth factor receptor targeted therapy in breast cancer

PubMed Central

Matsuda, Naoko; Lim, Bora; Wang, Xiaoping; Ueno, Naoto T.

2018-01-01

Introduction Epidermal growth factor receptor (EGFR) targeted treatment has been evaluated but has not shown a clear clinical benefit for breast cancer. This review article aims to consider the knowledge of the biological background of EGFR pathways in dissecting clinical studies of EGFR targeted treatment in breast cancer. Areas covered This review focuses on the role of the EGFR pathway and the investigational drugs that target EGFR for breast cancer. Expert opinion Recent studies have indicated that EGFR targeted therapy for breast cancer has some promising effects for patients with triple-negative breast cancer, basal-like breast cancer, and inflammatory breast cancer. However, predictive and prognostic biomarkers for EGFR targeted therapy have not been identified. The overexpression or amplification of EGFR itself may not be the true factor of induction of the canonical pathway as an oncogenic driver of breast cancer. Instead, downstream, non-canonical pathways related to EGFR may contribute to some aspects of the biological behavior of breast cancer; therefore, the blockade of the receptor could result in sufficient suppression of downstream pathways to inhibit the aggressive behavior of breast cancer. Mechanistic studies to investigate the dynamic interaction between the EGFR pathway and non-canonical pathways are warranted. PMID:28271910

Effects of targeting lower versus higher arterial oxygen saturations on death or disability in preterm infants.

PubMed

Askie, Lisa M; Darlow, Brian A; Davis, Peter G; Finer, Neil; Stenson, Ben; Vento, Maximo; Whyte, Robin

2017-04-11

The use of supplemental oxygen in the care of extremely preterm infants has been common practice since the 1940s. Despite this, there is little agreement regarding which oxygen saturation (SpO₂) ranges to target to maximise short- or long-term growth and development, while minimising harms. There are two opposing concerns. Lower oxygen levels (targeting SpO₂ at 90% or less) may impair neurodevelopment or result in death. Higher oxygen levels (targeting SpO₂ greater than 90%) may increase severe retinopathy of prematurity or chronic lung disease.The use of pulse oximetry to non-invasively assess neonatal SpO₂ levels has been widespread since the 1990s. Until recently there were no randomised controlled trials (RCTs) that had assessed whether it is better to target higher or lower oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result, there is significant international practice variation and uncertainty remains as to the most appropriate range to target oxygen saturation levels in preterm and low birth weight infants. 1. What are the effects of targeting lower versus higher oxygen saturation ranges on death or major neonatal and infant morbidities, or both, in extremely preterm infants?2. Do these effects differ in different types of infants, including those born at a very early gestational age, or in those who are outborn, without antenatal corticosteroid coverage, of male sex, small for gestational age or of multiple birth, or by mode of delivery? We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1966 to 11 April 2016), Embase (1980 to 11 April 2016) and CINAHL (1982 to 11 April 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials. Randomised controlled trials that enrolled babies born at less than 28

Targeting Anti-Insulin B Cell Receptors Improves Receptor Editing in Type 1 Diabetes-Prone Mice1, 2, 3

PubMed Central

Bonami, Rachel H.; Thomas, James W.

2015-01-01

Autoreactive B lymphocytes that commonly arise in the developing repertoire can be salvaged by receptor editing, a central tolerance mechanism that alters BCR specificity through continued L chain rearrangement. It is unknown whether autoantigens with weak cross-linking potential, such as insulin, elicit receptor editing, or if this process is dysregulated in related autoimmunity. To resolve these issues, an editing-competent model was developed in which anti-insulin Vκ125 was targeted to the Igκ locus and paired with anti-insulin VH125Tg. Physiologic, circulating insulin increased RAG-2 expression and was associated with BCR replacement that eliminated autoantigen recognition in a proportion of developing anti-insulin B lymphocytes. The proportion of anti-insulin B cells that underwent receptor editing was reduced in the type 1 diabetes-prone NOD strain relative to a non-autoimmune strain. Resistance to editing was associated with increased surface IgM expression on immature (but not transitional or mature) anti-insulin B cells in the NOD strain. The actions of mAb123 on central tolerance were also investigated, as selective targeting of insulin-occupied BCR by mAb123 eliminates anti-insulin B lymphocytes and prevents type 1 diabetes. Autoantigen-targeting by mAb123 increased RAG-2 expression and dramatically enhanced BCR replacement in newly developed B lymphocytes. Administering F(ab’)2123 induced IgM downregulation and reduced the frequency of anti-insulin B lymphocytes within the polyclonal repertoire of VH125Tg/NOD mice, suggesting enhanced central tolerance by direct BCR interaction. These findings indicate that weak or faulty checkpoints for central tolerance can be overcome by autoantigen-specific immunomodulatory therapy. PMID:26432895

Folate receptor‐targeted aminoglycoside‐derived polymers for transgene expression in cancer cells

PubMed Central

Godeshala, Sudhakar; Nitiyanandan, Rajeshwar; Thompson, Brian; Goklany, Sheba; Nielsen, David R.

2016-01-01

Abstract Targeted delivery of anticancer therapeutics can potentially overcome the limitations associated with current chemotherapeutic regimens. Folate receptors are overexpressed in several cancers, including ovarian, triple‐negative breast and bladder cancers, making them attractive for targeted delivery of nucleic acid therapeutics to these tumors. This work describes the synthesis, characterization and evaluation of folic acid‐conjugated, aminoglycoside‐derived polymers for targeted delivery of transgenes to breast and bladder cancer cell lines. Transgene expression was significantly higher with FA‐conjugated aminoglycoside‐derived polymers than with Lipofectamine, and these polymers demonstrated minimal cytotoxicty. Competitive inhibition using free folic acid significantly reduced transgene expression efficacy of folate‐targeted polymers, suggesting a role for folate receptor‐mediated uptake. High efficacy FA‐targeted polymers were employed to deliver a plasmid expressing the TRAIL protein, which induced death in cancer cells. These results indicate that FA‐conjugated aminoglycoside‐derived polymers are promising for targeted delivery of nucleic acids to cancer cells that overexpress folate receptors. PMID:29313013

BMP type II receptor as a therapeutic target in pulmonary arterial hypertension.

PubMed

Orriols, Mar; Gomez-Puerto, Maria Catalina; Ten Dijke, Peter

2017-08-01

Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive elevation in mean pulmonary arterial pressure. This occurs due to abnormal remodeling of small peripheral lung vasculature resulting in progressive occlusion of the artery lumen that eventually causes right heart failure and death. The most common cause of PAH is inactivating mutations in the gene encoding a bone morphogenetic protein type II receptor (BMPRII). Current therapeutic options for PAH are limited and focused mainly on reversal of pulmonary vasoconstriction and proliferation of vascular cells. Although these treatments can relieve disease symptoms, PAH remains a progressive lethal disease. Emerging data suggest that restoration of BMPRII signaling in PAH is a promising alternative that could prevent and reverse pulmonary vascular remodeling. Here we will focus on recent advances in rescuing BMPRII expression, function or signaling to prevent and reverse pulmonary vascular remodeling in PAH and its feasibility for clinical translation. Furthermore, we summarize the role of described miRNAs that directly target the BMPR2 gene in blood vessels. We discuss the therapeutic potential and the limitations of promising new approaches to restore BMPRII signaling in PAH patients. Different mutations in BMPR2 and environmental/genetic factors make PAH a heterogeneous disease and it is thus likely that the best approach will be patient-tailored therapies.

Receptor tyrosine kinases play a significant role in human oligodendrocyte inflammation and cell death associated with the Lyme disease bacterium Borrelia burgdorferi.

PubMed

Parthasarathy, Geetha; Philipp, Mario T

2017-05-30

In previous studies, human oligodendrocytes were demonstrated to undergo apoptosis in the presence of Borrelia burgdorferi under an inflammatory milieu. Subsequently, we determined that the MEK/ERK pathway played a significant role in triggering downstream inflammation as well as apoptosis. However, the identity of receptors triggered by exposure to B. burgdorferi and initiating signaling events was unknown. In this study, we explored the role of several TLR and EGFR/FGFR/PDGFR tyrosine kinase pathways in inducing inflammation in the presence of B. burgdorferi, using siRNA and/or inhibitors, in MO3.13 human oligodendrocytes. Cell death and apoptosis assays were also carried out in the presence or absence of specific receptor inhibitors along with the bacteria to determine the role of these receptors in apoptosis induction. The expression pattern of specific receptors with or without B. burgdorferi was also determined. TLRs 2 and 5 had a minimal role in inducing inflammation, particularly IL-6 production. Rather, their effect was mostly inhibitory, with TLR2 downregulation significantly upregulating CXCL8, and CXCL (1,2,3) levels, and TLR5 likely having a similar role in CXCL8, CXCL(1,2,3), and CCL5 levels. TLR4 contributed mostly towards CCL5 production. On the other hand, inhibition of all three EGF/FGF/PDGF receptors significantly downregulated all five of the inflammatory mediators tested even in the presence of B. burgdorferi. Their inhibition also downregulated overall cell death and apoptosis levels. The expression pattern of these receptors, as assessed by immunohistochemistry indicated that the PDGFRβ receptor was the most predominantly expressed receptor, followed by FGFR, although no significant differences were discernible between presence and absence of bacteria. Interestingly, inhibition of individual EGFR, FGFR, or PDGFR receptors did not indicate an individual role for any of these receptors in the overall downregulation of pathogenesis. Contrarily

Bladder sensory physiology: neuroactive compounds and receptors, sensory transducers, and target-derived growth factors as targets to improve function

PubMed Central

Gonzalez, Eric J.; Merrill, Liana

2014-01-01

Urinary bladder dysfunction presents a major problem in the clinical management of patients suffering from pathological conditions and neurological injuries or disorders. Currently, the etiology underlying altered visceral sensations from the urinary bladder that accompany the chronic pain syndrome, bladder pain syndrome (BPS)/interstitial cystitis (IC), is not known. Bladder irritation and inflammation are histopathological features that may underlie BPS/IC that can change the properties of lower urinary tract sensory pathways (e.g., peripheral and central sensitization, neurochemical plasticity) and contribute to exaggerated responses of peripheral bladder sensory pathways. Among the potential mediators of peripheral nociceptor sensitization and urinary bladder dysfunction are neuroactive compounds (e.g., purinergic and neuropeptide and receptor pathways), sensory transducers (e.g., transient receptor potential channels) and target-derived growth factors (e.g., nerve growth factor). We review studies related to the organization of the afferent limb of the micturition reflex and discuss neuroplasticity in an animal model of urinary bladder inflammation to increase the understanding of functional bladder disorders and to identify potential novel targets for development of therapeutic interventions. Given the heterogeneity of BPS/IC and the lack of consistent treatment benefits, it is unlikely that a single treatment directed at a single target in micturition reflex pathways will have a mass benefit. Thus, the identification of multiple targets is a prudent approach, and use of cocktail treatments directed at multiple targets should be considered. PMID:24760999

Aflatoxin B1 affects apoptosis and expression of death receptor and endoplasmic reticulum molecules in chicken spleen.

PubMed

Zhu, Panpan; Zuo, Zhicai; Zheng, Zhixiang; Wang, Fengyuan; Peng, Xi; Fang, Jing; Cui, Hengmin; Gao, Caixia; Song, Hetao; Zhou, Yi; Liu, Xici

2017-11-21

Aflatoxin B 1 (AFB 1 ) is a natural product of the Aspergillus genus of molds, which grow on several foodstuffs stored in hot moist conditions, and is among the most potent hepatocarcinogens and immunosuppression presently known. The latter was related to the up-regulated apoptosis of immune organs. However, the effect of expression of death receptor and endoplasmic reticulum molecules in AFB 1 -induced apoptosis of chicken splenocytes was largely unknown. The objective of this study was to investigate this unknown field. One hundred and forty four one-day-old chickens were randomly divided into control group (0 mg/kg AFB 1 ) and AFB 1 group (0.6 mg/kg AFB 1 ), respectively and fed with AFB 1 for 21 days. Histological observation demonstrated that AFB 1 caused slight congestion and lymphocytic depletion in the spleen. TUNEL and flow cytometry assays showed the excessive apoptosis of splenocytes provoked by AFB 1 . Moreover, quantitative real-time PCR analysis revealed that AFB 1 induced the elevated mRNA expression of Fas, FasL, TNF-α, TNF-R 1 , Caspase-3, Caspase-8, Caspase-10, Grp78 and Grp94 in the spleen. These findings suggested that AFB 1 could lead the excessive apoptosis and alter the expression of death receptor and endoplasmic reticulum molecules in chicken spleen.

The 5-HT7 receptor as a potential target for treating drug and alcohol abuse

PubMed Central

Hauser, Sheketha R.; Hedlund, Peter B.; Roberts, Amanda J.; Sari, Youssef; Bell, Richard L.; Engleman, Eric A.

2015-01-01

Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed—including the mesocorticolimbic dopamine (MCL-DA) system and the extended amygdala. The serotonin (5-HT) neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT7 receptor as a novel target for treating addiction. PMID:25628528

The Target Residence Time of Antihistamines Determines Their Antagonism of the G Protein-Coupled Histamine H1 Receptor

PubMed Central

Bosma, Reggie; Witt, Gesa; Vaas, Lea A. I.; Josimovic, Ivana; Gribbon, Philip; Vischer, Henry F.; Gul, Sheraz; Leurs, Rob

2017-01-01

The pharmacodynamics of drug-candidates is often optimized by metrics that describe target binding (Kd or Ki value) or target modulation (IC50). However, these metrics are determined at equilibrium conditions, and consequently information regarding the onset and offset of target engagement and modulation is lost. Drug-target residence time is a measure for the lifetime of the drug-target complex, which has recently been receiving considerable interest, as target residence time is shown to have prognostic value for the in vivo efficacy of several drugs. In this study, we have investigated the relation between the increased residence time of antihistamines at the histamine H1 receptor (H1R) and the duration of effective target-inhibition by these antagonists. Hela cells, endogenously expressing low levels of the H1R, were incubated with a series of antihistamines and dissociation was initiated by washing away the unbound antihistamines. Using a calcium-sensitive fluorescent dye and a label free, dynamic mass redistribution based assay, functional recovery of the H1R responsiveness was measured by stimulating the cells with histamine over time, and the recovery was quantified as the receptor recovery time. Using these assays, we determined that the receptor recovery time for a set of antihistamines differed more than 40-fold and was highly correlated to their H1R residence times, as determined with competitive radioligand binding experiments to the H1R in a cell homogenate. Thus, the receptor recovery time is proposed as a cell-based and physiologically relevant metric for the lead optimization of G protein-coupled receptor antagonists, like the H1R antagonists. Both, label-free or real-time, classical signaling assays allow an efficient and physiologically relevant determination of kinetic properties of drug molecules. PMID:29033838

Bitter taste receptors as targets for tocolytics in preterm labor therapy.

PubMed

Zheng, Kaizhi; Lu, Ping; Delpapa, Ellen; Bellve, Karl; Deng, Ruitang; Condon, Jennifer C; Fogarty, Kevin; Lifshitz, Lawrence M; Simas, Tiffany A Moore; Shi, Fangxiong; ZhuGe, Ronghua

2017-09-01

Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity, with few prevention and treatment options. Uterine contraction is a central feature of PTB, so gaining new insights into the mechanisms of this contraction and consequently identifying novel targets for tocolytics are essential for more successful management of PTB. Here we report that myometrial cells from human and mouse express bitter taste receptors (TAS2Rs) and their canonical signaling components ( i.e., G-protein gustducin and phospholipase C β2). Bitter tastants can completely relax myometrium precontracted by different uterotonics. In isolated single mouse myometrial cells, a phenotypical bitter tastant (chloroquine, ChQ) reverses the rise in intracellular Ca 2+ concentration ([Ca 2+ ] i ) and cell shortening induced by uterotonics, and this reversal effect is inhibited by pertussis toxin and by genetic deletion of α-gustducin. In human myometrial cells, knockdown of TAS2R14 but not TAS2R10 inhibits ChQ's reversal effect on an oxytocin-induced rise in [Ca 2+ ] i Finally, ChQ prevents mouse PTBs induced by bacterial endotoxin LPS or progesterone receptor antagonist mifepristone more often than current commonly used tocolytics, and this prevention is largely lost in α-gustducin-knockout mice. Collectively, our results reveal that activation of the canonical TAS2R signaling system in myometrial cells produces profound relaxation of myometrium precontracted by a broad spectrum of contractile agonists, and that targeting TAS2Rs is an attractive approach to developing effective tocolytics for PTB management.-Zheng, K., Lu, P., Delpapa, E., Bellve, K., Deng, R., Condon, J. C., Fogarty, K., Lifshitz, L. M., Simas, T. A. M., Shi, F., ZhuGe, R. Bitter taste receptors as targets for tocolytics in preterm labor therapy. © FASEB.

Contrasting skeletal phenotypes in mice with an identical mutation targeted to thyroid hormone receptor alpha1 or beta.

PubMed

O'Shea, Patrick J; Bassett, J H Duncan; Sriskantharajah, Srividya; Ying, Hao; Cheng, Sheue-yann; Williams, Graham R

2005-12-01

Thyroid hormone (T(3)) regulates bone turnover and mineralization in adults and is essential for skeletal development. Surprisingly, we identified a phenotype of skeletal thyrotoxicosis in T(3) receptor beta(PV) (TRbeta(PV)) mice in which a targeted frameshift mutation in TRbeta results in resistance to thyroid hormone. To characterize mechanisms underlying thyroid hormone action in bone, we analyzed skeletal development in TRalpha1(PV) mice in which the same PV mutation was targeted to TRalpha1. In contrast to TRbeta(PV) mice, TRalpha1(PV) mutants exhibited skeletal hypothyroidism with delayed endochondral and intramembranous ossification, severe postnatal growth retardation, diminished trabecular bone mineralization, reduced cortical bone deposition, and delayed closure of the skull sutures. Skeletal hypothyroidism in TRalpha1(PV) mutants was accompanied by impaired GH receptor and IGF-I receptor expression and signaling in the growth plate, whereas GH receptor and IGF-I receptor expression and signaling were increased in TRbeta(PV) mice. These data indicate that GH receptor and IGF-I receptor are physiological targets for T(3) action in bone in vivo. The divergent phenotypes observed in TRalpha1(PV) and TRbeta(PV) mice arise because the pituitary gland is a TRbeta-responsive tissue, whereas bone is TRalpha responsive. These studies provide a new understanding of the complex relationship between central and peripheral thyroid status.

Anabolic Androgenic Steroid (AAS) Related Deaths: Autoptic, Histopathological and Toxicological Findings

PubMed Central

Frati, Paola; Busardò, Francesco P.; Cipolloni, Luigi; Dominicis, Enrico De; Fineschi, Vittorio

2015-01-01

Anabolic androgenic steroids (AASs) represent a large group of synthetic derivatives of testosterone, produced to maximize anabolic effects and minimize the androgenic ones. AAS can be administered orally, parenterally by intramuscular injection and transdermally. Androgens act by binding to the nuclear androgen receptor (AR) in the cytoplasm and then translocate into the nucleus. This binding results in sequential conformational changes of the receptor affecting the interaction between receptor and protein, and receptor and DNA. Skeletal muscle can be considered as the main target tissue for the anabolic effects of AAS, which are mediated by ARs which after exposure to AASs are up-regulated and their number increases with body building. Therefore, AASs determine an increase in muscle size as a consequence of a dose-dependent hypertrophy resulting in an increase of the cross-sectional areas of both type I and type II muscle fibers and myonuclear domains. Moreover, it has been reported that AASs can increase tolerance to exercise by making the muscles more capable to overload therefore shielding them from muscle fiber damage and improving the level of protein synthesis during recovery. Despite some therapeutic use of AASs, there is also wide abuse among athletes especially bodybuilders in order to improve their performances and to increase muscle growth and lean body mass, taking into account the significant anabolic effects of these drugs. The prolonged misuse and abuse of AASs can determine several adverse effects, some of which may be even fatal especially on the cardiovascular system because they may increase the risk of sudden cardiac death (SCD), myocardial infarction, altered serum lipoproteins, and cardiac hypertrophy. The aim of this review is to focus on deaths related to AAS abuse, trying to evaluate the autoptic, histopathological and toxicological findings in order to investigate the pathophysiological mechanism that underlines this type of death, which

Tumor-targeting peptides from combinatorial libraries*

PubMed Central

Liu, Ruiwu; Li, Xiaocen; Xiao, Wenwu; Lam, Kit S.

2018-01-01

Cancer is one of the major and leading causes of death worldwide. Two of the greatest challenges infighting cancer are early detection and effective treatments with no or minimum side effects. Widespread use of targeted therapies and molecular imaging in clinics requires high affinity, tumor-specific agents as effective targeting vehicles to deliver therapeutics and imaging probes to the primary or metastatic tumor sites. Combinatorial libraries such as phage-display and one-bead one-compound (OBOC) peptide libraries are powerful approaches in discovering tumor-targeting peptides. This review gives an overview of different combinatorial library technologies that have been used for the discovery of tumor-targeting peptides. Examples of tumor-targeting peptides identified from each combinatorial library method will be discussed. Published tumor-targeting peptide ligands and their applications will also be summarized by the combinatorial library methods and their corresponding binding receptors. PMID:27210583

Targeting C-type lectin receptors: a high-carbohydrate diet for dendritic cells to improve cancer vaccines

PubMed Central

van Dinther, Dieke; Stolk, Dorian A.; van de Ven, Rieneke; van Kooyk, Yvette; de Gruijl, Tanja D.; den Haan, Joke M. M.

2017-01-01

There is a growing understanding of why certain patients do or do not respond to checkpoint inhibition therapy. This opens new opportunities to reconsider and redevelop vaccine strategies to prime an anticancer immune response. Combination of such vaccines with checkpoint inhibitors will both provide the fuel and release the brake for an efficient anticancer response. Here, we discuss vaccine strategies that use C-type lectin receptor (CLR) targeting of APCs, such as dendritic cells and macrophages. APCs are a necessity for the priming of antigen-specific cytotoxic and helper T cells. Because CLRs are natural carbohydrate-recognition receptors highly expressed by multiple subsets of APCs and involved in uptake and processing of Ags for presentation, these receptors seem particularly interesting for targeting purposes. PMID:28729358

Differential Induction of Immunogenic Cell Death and Interferon Expression in Cancer Cells by Structured ssRNAs.

PubMed

Lee, Jaewoo; Lee, Youngju; Xu, Li; White, Rebekah; Sullenger, Bruce A

2017-06-07

Activation of the RNA-sensing pattern recognition receptor (PRR) in cancer cells leads to cell death and cytokine expression. This cancer cell death releases tumor antigens and damage-associated molecular patterns (DAMPs) that induce anti-tumor immunity. However, these cytokines and DAMPs also cause adverse inflammatory and thrombotic complications that can limit the overall therapeutic benefits of PRR-targeting anti-cancer therapies. To overcome this problem, we generated and evaluated two novel and distinct ssRNA molecules (immunogenic cell-killing RNA [ICR]2 and ICR4). ICR2 and ICR4 differentially stimulated cell death and PRR signaling pathways and induced different patterns of cytokine expression in cancer and innate immune cells. Interestingly, DAMPs released from ICR2- and ICR4-treated cancer cells had distinct patterns of stimulation of innate immune receptors and coagulation. Finally, ICR2 and ICR4 inhibited in vivo tumor growth as effectively as poly(I:C). ICR2 and ICR4 are potential therapeutic agents that differentially induce cell death, immune stimulation, and coagulation when introduced into tumors. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Glycoprotein CD98 as a receptor for colitis-targeted delivery of nanoparticle.

PubMed

Xiao, Bo; Yang, Yang; Viennois, Emilie; Zhang, Yuchen; Ayyadurai, Saravanan; Baker, Mark; Laroui, Hamed; Merlin, Didier

2014-03-21

Treatment strategies for inflammatory bowel disease have been constrained by limited therapeutic efficacy and serious adverse effects owing to a lack of receptor for targeted drug delivery to the inflamed colon. Upon inflammation, CD98 expression is highly elevated in colonic epithelial cells and infiltrating immune cells. To investigate whether CD98 can be used as a colitis-targeted delivery receptor, we constructed CD98 Fab'-bearing quantum dots (QDs)-loaded nanoparticles (Fab'-NPs). The resultant Fab'-NPs had desired particle size (~458 nm) with a narrow size distribution and zeta-potential (approximately +19 mV), low cytotoxicity, and excellent fluorescence properties. Electron microscopy images provided direct evidence for the well-dispersed distribution of QDs within spherical Fab'-NPs. Cellular uptake experiments demonstrated that Fab'-NPs were efficiently internalized into Colon-26 and RAW 264.7 cells through the CD98-mediated endocytosis pathway, and showed that the targeting effect of CD98 Fab' markedly increased their cellular uptake efficiency compared with control pegylated QDs-loaded NPs (PEG-NPs). Furthermore, ex vivo studies showed much more effective accumulation of Fab'-NPs in colitis tissue than that of PEG-NPs. These findings suggest that because of inflammation-dependent over-expression of CD98, active colitis-targeted delivery can be accomplished using NPs decorated with CD98 antibody.

Non-synaptic receptors and transporters involved in brain functions and targets of drug treatment.

PubMed

Vizi, E S; Fekete, A; Karoly, R; Mike, A

2010-06-01

Beyond direct synaptic communication, neurons are able to talk to each other without making synapses. They are able to send chemical messages by means of diffusion to target cells via the extracellular space, provided that the target neurons are equipped with high-affinity receptors. While synaptic transmission is responsible for the 'what' of brain function, the 'how' of brain function (mood, attention, level of arousal, general excitability, etc.) is mainly controlled non-synaptically using the extracellular space as communication channel. It is principally the 'how' that can be modulated by medicine. In this paper, we discuss different forms of non-synaptic transmission, localized spillover of synaptic transmitters, local presynaptic modulation and tonic influence of ambient transmitter levels on the activity of vast neuronal populations. We consider different aspects of non-synaptic transmission, such as synaptic-extrasynaptic receptor trafficking, neuron-glia communication and retrograde signalling. We review structural and functional aspects of non-synaptic transmission, including (i) anatomical arrangement of non-synaptic release sites, receptors and transporters, (ii) intravesicular, intra- and extracellular concentrations of neurotransmitters, as well as the spatiotemporal pattern of transmitter diffusion. We propose that an effective general strategy for efficient pharmacological intervention could include the identification of specific non-synaptic targets and the subsequent development of selective pharmacological tools to influence them.

Activation of TRKA receptor elicits mastocytosis in mice and is involved in the development of resistance to KIT-targeted therapy.

PubMed

Yang, Min; Pan, Zengkai; Huang, Kezhi; Büsche, Guntram; Feuerhake, Friedrich; Chaturvedi, Anuhar; Nie, Danian; Heuser, Michael; Thol, Felicitas; von Neuhoff, Nils; Ganser, Arnold; Li, Zhixiong

2017-09-26

The neurotrophins (NTs) play a key role in neuronal survival and maintenance. The TRK (tropomyosin-related kinase) tyrosine kinase receptors (TRKA, TRKB, TRKC) are high affinity receptors for NTs. There is increasing data demonstrating an important role of the TRK family in cancer initiation and progression. NTs have been known for many years to promote chemotaxis, maturation, and survival of mast cells. However, the role of NT signaling in the pathogenesis of mastocytosis is not well understood. In this study, we demonstrate that activation of TRKA by its ligand nerve growth factor (NGF) is potent to trigger a disease in mice with striking similarities to human systemic mastocytosis (SM). Moreover, activation of TRKA by NGF strongly rescues KIT inhibition-induced cell death of mast cell lines and primary mast cells from patients with SM, and this rescue effect can be efficiently blocked by entrectinib (a new pan TRK specific inhibitor). HMC-1 mast cell leukemia cells that are resistant to KIT inhibition induced by TRKA activation show reactivation of MAPK/ERK (extracellular signal-regulated kinase) and strong upregulation of early growth response 3 (EGR3), suggesting an important role of MAPK-EGR3 axis in the development of resistance to KIT inhibition. Targeting both TRK and KIT significantly prolongs survival of mice xenotransplanted with HMC-1 cells compared with targeting KIT alone. Thus, these data strongly suggest that TRKA signaling can improve neoplastic mast cell fitness. This might explain at least in part why treatment with KIT inhibitors alone so far has been disappointing in most published clinical trials for mastocytosis. Our data suggest that targeting both KIT and TRKs might improve efficacy of molecular therapy in SM with KIT mutations.

Activation of innate antiviral immune response via double-stranded RNA-dependent RLR receptor-mediated necroptosis

PubMed Central

Wang, Wei; Wang, Wei-Hua; Azadzoi, Kazem M.; Su, Ning; Dai, Peng; Sun, Jianbin; Wang, Qin; Liang, Ping; Zhang, Wentao; Lei, Xiaoying; Yan, Zhen; Yang, Jing-Hua

2016-01-01

Viruses induce double-stranded RNA (dsRNA) in the host cells. The mammalian system has developed dsRNA-dependent recognition receptors such as RLRs that recognize the long stretches of dsRNA as PAMPs to activate interferon-mediated antiviral pathways and apoptosis in severe infection. Here we report an efficient antiviral immune response through dsRNA-dependent RLR receptor-mediated necroptosis against infections from different classes of viruses. We demonstrated that virus-infected A549 cells were efficiently killed in the presence of a chimeric RLR receptor, dsCARE. It measurably suppressed the interferon antiviral pathway but promoted IL-1β production. Canonical cell death analysis by morphologic assessment, phosphatidylserine exposure, caspase cleavage and chemical inhibition excluded the involvement of apoptosis and consistently suggested RLR receptor-mediated necroptosis as the underlying mechanism of infected cell death. The necroptotic pathway was augmented by the formation of RIP1-RIP3 necrosome, recruitment of MLKL protein and the activation of cathepsin D. Contributing roles of RIP1 and RIP3 were confirmed by gene knockdown. Furthermore, the necroptosis inhibitor necrostatin-1 but not the pan-caspase inhibitor zVAD impeded dsCARE-dependent infected cell death. Our data provides compelling evidence that the chimeric RLR receptor shifts the common interferon antiviral responses of infected cells to necroptosis and leads to rapid death of the virus-infected cells. This mechanism could be targeted as an efficient antiviral strategy. PMID:26935990

Chimeric antigen receptor T cells targeting Fc μ receptor selectively eliminate CLL cells while sparing healthy B cells.

PubMed

Faitschuk, Elena; Hombach, Andreas A; Frenzel, Lukas P; Wendtner, Clemens-Martin; Abken, Hinrich

2016-09-29

Adoptive cell therapy of chronic lymphocytic leukemia (CLL) with chimeric antigen receptor (CAR)-modified T cells targeting CD19 induced lasting remission of this refractory disease in a number of patients. However, the treatment is associated with prolonged "on-target off-tumor" toxicities due to the targeted elimination of healthy B cells demanding more selectivity in targeting CLL cells. We identified the immunoglobulin M Fc receptor (FcμR), also known as the Fas apoptotic inhibitory molecule-3 or TOSO, as a target for a more selective treatment of CLL by CAR T cells. FcμR is highly and consistently expressed by CLL cells; only minor levels are detected on healthy B cells or other hematopoietic cells. T cells with a CAR specific for FcμR efficiently responded toward CLL cells, released a panel of proinflammatory cytokines and lytic factors, like soluble FasL and granzyme B, and eliminated the leukemic cells. In contrast to CD19 CAR T cells, anti-FcμR CAR T cells did not attack healthy B cells. T cells with anti-FcμR CAR delayed outgrowth of Mec-1-induced leukemia in a xenograft mouse model. T cells from CLL patients in various stages of the disease, modified by the anti-FcμR CAR, purged their autologous CLL cells in vitro without reducing the number of healthy B cells, which is the case with anti-CD19 CAR T cells. Compared with the currently used therapies, the data strongly imply a superior therapeutic index of anti-FcμR CAR T cells for the treatment of CLL. © 2016 by The American Society of Hematology.

Emerging strategies for EphA2 receptor targeting for cancer therapeutics.

PubMed

Tandon, Manish; Vemula, Sai Vikram; Mittal, Suresh K

2011-01-01

High mortality rates with cancers warrant further development of earlier diagnostics and better treatment strategies. Membrane-bound erythropoietin-producing hepatocellular receptor tyrosine kinase class A2 (EphA2) is overexpressed in breast, prostate, urinary bladder, skin, lung, ovary and brain cancers. EphA2 overexpression in cancers, its signaling mechanisms and strategies to target its deregulation. High EphA2 expression in cancer cells is correlated with a poor prognosis associated with recurrence due to enhanced metastasis. Interaction of the EphA2 receptor with its ligand (e.g., ephrinA1) triggers events that are deregulated and implicated in carcinogenesis. EphrinA1-independent oncogenic activity and ephrinA1-dependent tumor suppressor roles for EphA2 are described. Molecular interactions of EphA2 with signaling proteins are associated with the modulation of cytoskeleton dynamics, cell adhesion, proliferation, differentiation and metastasis. The deregulated signaling by EphA2 and its involvement in oncogenesis provide multiple avenues for the rational design of intervention approaches. EphA2 has been tested as a drug target using multiple approaches such as agonist antibodies, RNA interference, immunotherapy, virus vector-mediated gene transfer, small-molecule inhibitors and nanoparticles. With over a decade of research, encouraging results with targeting of EphA2 expression in various pre-clinical cancer models necessitate further studies.

Tryptophanol-derived oxazolopiperidone lactams: identification of a hit compound as NMDA receptor antagonist.

PubMed

Pereira, Nuno A L; Sureda, Francesc X; Esplugas, Roser; Pérez, Maria; Amat, Mercedes; Santos, Maria M M

2014-08-01

N-Methyl-D-aspartate receptors (NMDAR) exacerbated activation leads to neuron death through a phenomenon called excitotoxicity. These receptors are implicated in several neurological diseases (e.g., Alzheimer and Parkinson) and thus represent an important therapeutic target. We herein describe the study of enantiopure tryptophanol-derived oxazolopiperidone lactams as NMDA receptor antagonists. The most active hit exhibited an IC50 of 63.4 μM in cultured rat cerebellar granule neurons thus being 1.5 fold more active than clinically approved NMDA antagonist amantadine (IC50=92 μM). Copyright © 2014 Elsevier Ltd. All rights reserved.

P2X7 receptor promotes intestinal inflammation in chemically induced colitis and triggers death of mucosal regulatory T cells.

PubMed

Figliuolo, Vanessa R; Savio, Luiz Eduardo Baggio; Safya, Hanaa; Nanini, Hayandra; Bernardazzi, Cláudio; Abalo, Alessandra; de Souza, Heitor S P; Kanellopoulos, Jean; Bobé, Pierre; Coutinho, Cláudia M L M; Coutinho-Silva, Robson

2017-06-01

P2X7 receptor activation contributes to inflammation development in different pathologies. We previously reported that the P2X7 receptor is over-expressed in the gut mucosa of patients with inflammatory bowel disease, and that P2X7 inhibition protects against chemically induced colitis. Here, we investigated in detail the role of the P2X7 receptor in inflammatory bowel disease development, by treating P2X7 knockout (KO) and WT mice with two different (and established) colitis inductors. P2X7 KO mice were protected against gut inflammation induced by 2,4,6-trinitrobenzenesulfonic acid or oxazolone, with no weight loss or gut histological alterations after treatment. P2X7 receptor knockout induced regulatory T cell accumulation in the colon, as evaluated by qRT-PCR for FoxP3 expression and immunostaining for CD90/CD45RB low . Flow cytometry analysis of mesenteric lymph node cells showed that P2X7 activation (by ATP) triggered regulatory T cell death. In addition, such cells from P2X7 KO mice expressed more CD103, suggesting increased migration of regulatory T cells to the colon (relative to the WT). Our results show that the P2X7 has a key role during inflammation development in inflammatory bowel disease, by triggering the death and retention in the mesenteric lymph nodes of regulatory T cells that would otherwise promote immune system tolerance in the gut. Copyright © 2017 Elsevier B.V. All rights reserved.

miR-14 regulates autophagy during developmental cell death by targeting ip3-kinase 2.

PubMed

Nelson, Charles; Ambros, Victor; Baehrecke, Eric H

2014-11-06

Macroautophagy (autophagy) is a lysosome-dependent degradation process that has been implicated in age-associated diseases. Autophagy is involved in both cell survival and cell death, but little is known about the mechanisms that distinguish its use during these distinct cell fates. Here, we identify the microRNA miR-14 as being both necessary and sufficient for autophagy during developmentally regulated cell death in Drosophila. Loss of miR-14 prevented induction of autophagy during salivary gland cell death, but had no effect on starvation-induced autophagy in the fat body. Moreover, misexpression of miR-14 was sufficient to prematurely induce autophagy in salivary glands, but not in the fat body. Importantly, miR-14 regulates this context-specific autophagy through its target, inositol 1,4,5-trisphosphate kinase 2 (ip3k2), thereby affecting inositol 1,4,5-trisphosphate (IP3) signaling and calcium levels during salivary gland cell death. This study provides in vivo evidence of microRNA regulation of autophagy through modulation of IP3 signaling. Copyright © 2014 Elsevier Inc. All rights reserved.

Sigma-1 receptor deficiency reduces MPTP-induced parkinsonism and death of dopaminergic neurons

PubMed Central

Hong, J; Sha, S; Zhou, L; Wang, C; Yin, J; Chen, L

2015-01-01

Sigma-1 receptor (σ1R) has been reported to be decreased in nigrostriatal motor system of Parkinson's disease patients. Using heterozygous and homozygous σ1R knockout (σ1R+/− and σ1R−/−) mice, we investigated the influence of σ1R deficiency on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-impaired nigrostriatal motor system. The injection of MPTP for 5 weeks in wild-type mice (MPTP-WT mice), but not in σ1R+/− or σ1R−/− mice (MPTP-σ1R+/− or MPTP-σ1R−/− mice), caused motor deficits and ~40% death of dopaminergic neurons in substantia nigra pars compacta with an elevation of N-methyl-d-aspartate receptor (NMDAr) NR2B phosphorylation. The σ1R antagonist NE100 or the NR2B inhibitor Ro25-6981 could alleviate the motor deficits and the death of dopaminergic neurons in MPTP-WT mice. By contrast, MPTP-σ1R+/− mice treated with the σ1R agonist PRE084 or MPTP-σ1R−/− mice treated with the NMDAr agonist NMDA appeared to have similar motor deficits and loss of dopaminergic neurons as MPTP-WT mice. The pharmacological or genetic inactivation of σ1R suppressed the expression of dopamine transporter (DAT) in substantia nigra, which was corrected by NMDA. The activation of σ1R by PRE084 enhanced the DAT expression in WT mice or σ1R+/− mice. By contrast, the level of vesicular monoamine transporter 2 (VMAT2) in σ1R+/− mice or σ1R−/− mice had no difference from WT mice. Interestingly, MPTP-WT mice showed the reduction in the levels of DAT and VMAT2, but MPTP-σ1R−/− mice did not. The inactivation of σ1R by NE100 could prevent the reduction of VMAT2 in MPTP-WT mice. In addition, the activation of microglia cells in substantia nigra was equally enhanced in MPTP-WT mice and MPTP-σ1R−/− mice. The number of activated astrocytes in MPTP-σ1R−/− mice was less than that in MPTP-WT mice. The findings indicate that the σ1R deficiency through suppressing NMDAr function and DAT expression can reduce MPTP-induced death of

Nicotinic ACh Receptors as Therapeutic Targets in CNS Disorders

PubMed Central

Dineley, Kelly T.; Pandya, Anshul A.; Yakel, Jerrel L.

2015-01-01

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor channels (nAChRs). These receptors are widely distributed throughout the central nervous system, being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in the mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer’s disease), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain. PMID:25639674

Nicotinic ACh receptors as therapeutic targets in CNS disorders.

PubMed

Dineley, Kelly T; Pandya, Anshul A; Yakel, Jerrel L

2015-02-01

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor (nAChR) channels. These receptors are widely distributed throughout the central nervous system (CNS), being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however, the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer's disease, AD), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain. Published by Elsevier Ltd.

FFA4 receptor (GPR120): A hot target for the development of anti-diabetic therapies.

PubMed

Liu, Hong-Da; Wang, Wen-bo; Xu, Zhi-gang; Liu, Chang-hong; He, Dong-fang; Du, Lv-Pei; Li, Min-Yong; Yu, Xiao; Sun, Jin-peng

2015-09-15

Free Fatty Acid 4 receptor (FFA4 receptor or GPR120), a rhodopsin-like G protein coupled receptor (GPCR) subfamily member, is a receptor that senses specific fatty acids such as ω-3 fatty acid in fish oil or the endogenous signaling lipid, PHASA. FFA4 receptor is enriched in lung, colon and adipose tissue but is also detected in many other tissues and cells. The activation of FFA4 receptor has multiple effects, including but not limited to inhibition of inflammation, improving insulin sensitivity and adipogenesis, and regulating hormone secretion from the gastro-intestinal system and pancreatic islets. The important role of FFA4 receptor in maintaining metabolic homeostasis strongly indicates the great potential of selective FFA4 receptor agonizts to treat diabetes and inflammation. In this review, we summarize recent research progress in the physiological and biochemical studies of FFA4 receptor and highlight its underlying signaling mechanisms and ligand identification to assist future research to exploit FFA4 receptor as a drug target. Copyright © 2015 Elsevier B.V. All rights reserved.

Targeting CB2-GPR55 Receptor Heteromers Modulates Cancer Cell Signaling*

PubMed Central

Moreno, Estefanía; Andradas, Clara; Medrano, Mireia; Caffarel, María M.; Pérez-Gómez, Eduardo; Blasco-Benito, Sandra; Gómez-Cañas, María; Pazos, M. Ruth; Irving, Andrew J.; Lluís, Carme; Canela, Enric I.; Fernández-Ruiz, Javier; Guzmán, Manuel; McCormick, Peter J.; Sánchez, Cristina

2014-01-01

The G protein-coupled receptors CB2 (CB2R) and GPR55 are overexpressed in cancer cells and human tumors. Because a modulation of GPR55 activity by cannabinoids has been suggested, we analyzed whether this receptor participates in cannabinoid effects on cancer cells. Here we show that CB2R and GPR55 form heteromers in cancer cells, that these structures possess unique signaling properties, and that modulation of these heteromers can modify the antitumoral activity of cannabinoids in vivo. These findings unveil the existence of previously unknown signaling platforms that help explain the complex behavior of cannabinoids and may constitute new targets for therapeutic intervention in oncology. PMID:24942731

Coengagement of CD16 and CD94 receptors mediates secretion of chemokines and induces apoptotic death of naive natural killer cells.

PubMed

Jewett, Anahid; Cacalano, Nicholas A; Head, Christian; Teruel, Antonia

2006-04-01

Down-modulation of CD16 (FcgammaRIII) receptors and loss of natural killer (NK) cell function have been observed in oral cancer patients. However, neither the mechanisms nor the significance of the decrease in CD16 receptors have been fully understood. The cytotoxic activity and survival of NK cells are negatively regulated by antibodies directed against CD16 surface receptor. The addition of anti-CD94 antibody in combination with either F(ab')(2) fragment or intact anti-CD16 antibody to NK cells resulted in significant inhibition of NK cell cytotoxic function and induction of apoptosis in resting human peripheral blood NK cells. Addition of interleukin-2 to anti-CD16 and/or anti-CD94 antibody-treated NK cells significantly inhibited apoptosis and increased the function of NK cells. There was a significant increase in tumor necrosis factor-alpha (TNF-alpha) but not IFN-gamma secretion in NK cells treated either with anti-CD16 antibody alone or in combination with anti-CD94 antibodies. Consequently, the addition of anti-TNF-alpha antibody partially inhibited apoptosis of NK cells mediated by the combination of anti-CD94 and anti-CD16 antibodies. Increase in apoptotic death of NK cells also correlated with an increase in type 2 inflammatory cytokines and in the induction of chemokines. Thus, we conclude that binding of antibodies to CD16 and CD94 NK cell receptors induces death of the NK cells and signals for the release of chemokines.

Glutamate metabotropic receptors as targets for drug therapy in epilepsy.

PubMed

Moldrich, Randal X; Chapman, Astrid G; De Sarro, Giovambattista; Meldrum, Brian S

2003-08-22

Metabotropic glutamate (mGlu) receptors have multiple actions on neuronal excitability through G-protein-linked modifications of enzymes and ion channels. They act presynaptically to modify glutamatergic and gamma-aminobutyric acid (GABA)-ergic transmission and can contribute to long-term changes in synaptic function. The recent identification of subtype-selective agonists and antagonists has permitted evaluation of mGlu receptors as potential targets in the treatment of epilepsy. Agonists acting on group I mGlu receptors (mGlu1 and mGlu5) are convulsant. Antagonists acting on mGlu1 or mGlu5 receptors are anticonvulsant against 3,5-dihydroxyphenylglycine (DHPG)-induced seizures and in mouse models of generalized motor seizures and absence seizures. The competitive, phenylglycine mGlu1/5 receptor antagonists generally require intracerebroventricular administration for potent anticonvulsant efficacy but noncompetitive antagonists, e.g., (3aS,6aS)-6a-naphthalen-2-ylmethyl-5-methyliden-hexahydrocyclopenta[c]furan-1-on (BAY36-7620), 2-methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP), and 2-methyl-6-(2-phenylethenyl)pyridine (SIB-1893) block generalized seizures with systemic administration. Agonists acting on group II mGlu receptors (mGlu2, mGlu3) to reduce glutamate release are anticonvulsant, e.g., 2R,4R-aminopyrrolidine-2,4-dicarboxylate [(2R,4R)-APDC], (+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (LY354740), and (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268). The classical agonists acting on group III mGlu receptors such as L-(+)-2-amino-4-phosphonobutyric acid, and L-serine-O-phosphate are acutely proconvulsant with some anticonvulsant activity. The more recently identified agonists (R,S)-4-phosphonophenylglycine [(R,S)-PPG] and (S)-3,4-dicarboxyphenylglycine [(S)-3,4-DCPG] and (1S,3R,4S)-1-aminocyclopentane-1,2,4-tricarboxylic acid [ACPT-1] are all anticonvulsant without proconvulsant effects. Studies in animal models of kindling

Effect of TLR ligands co-encapsulated with multiepitopic antigen in nanoliposomes targeted to human DCs via Fc receptor for cancer vaccines.

PubMed

Rueda, Felix; Eich, Christina; Cordobilla, Begoña; Domingo, Pere; Acosta, Gerardo; Albericio, Fernando; Cruz, Luis J; Domingo, Joan C

2017-11-01

Nanoliposomes (NLs) hold promise as new highly specific nanomedicine for anti-tumor vaccines, since they could be targeted to specific receptors on dendritic cell (DC) to induce maturation and activation and increase the anti-tumor immune response. Here we studied a NLs formulation targeted or not to FcR (the receptor for the IgG Fc fragment) for the treatment of androgen-responsive prostate cancer. Luteinizing-hormone-releasing hormone (LHRH) peptide (B- and T-cell epitopes), in tandem with a tetanus toxoid T-helper epitope (830-844 region) and several TLR (Toll-Like Receptor) ligands as adjuvants were co-encapsulated. Specific uptake in vitro of LHRH-TT liposomes targeted to the FcRs of human DCs was enhanced. DC maturation/activation, cytokine production and lymphocyte activation were consistently higher in targeted than non-targeted liposomes. Similar increase was observed as more adjuvants were administrated. Targeting to specific receptor and co-encapsulation of several TLR adjuvants are essential factors for the immune response in peptide based liposome vaccine. Copyright © 2017 Elsevier GmbH. All rights reserved.

Lysosomal Membrane Permeabilization is an Early Event in Sigma-2 Receptor Ligand Mediated Cell Death in Pancreatic Cancer

PubMed Central

2012-01-01

Background Sigma-2 receptor ligands have been studied for treatment of pancreatic cancer because they are preferentially internalized by proliferating cells and induce apoptosis. This mechanism of apoptosis is poorly understood, with varying reports of caspase-3 dependence. We evaluated multiple sigma-2 receptor ligands in this study, each shown to decrease tumor burden in preclinical models of human pancreatic cancer. Results Fluorescently labeled sigma-2 receptor ligands of two classes (derivatives of SW43 and PB282) localize to cell membrane components in Bxpc3 and Aspc1 pancreatic cancer cells and accumulate in lysosomes. We found that interactions in the lysosome are critical for cell death following sigma-2 ligand treatment because selective inhibition of a protective lysosomal membrane glycoprotein, LAMP1, with shRNA greatly reduced the viability of cells following treatment. Sigma-2 ligands induced lysosomal membrane permeabilization (LMP) and protease translocation triggering downstream effectors of apoptosis. Subsequently, cellular oxidative stress was greatly increased following treatment with SW43, and the hydrophilic antioxidant N-acetylcysteine (NAC) gave greater protection against this than a lipophilic antioxidant, α-tocopherol (α-toco). Conversely, PB282-mediated cytotoxicity relied less on cellular oxidation, even though α-toco did provide protection from this ligand. In addition, we found that caspase-3 induction was not as significantly inhibited by cathepsin inhibitors as by antioxidants. Both NAC and α-toco protected against caspase-3 induction following PB282 treatment, while only NAC offered protection following SW43 treatment. The caspase-3 inhibitor DEVD-FMK offered significant protection from PB282, but not SW43. Conclusions Sigma-2 ligand SW43 commits pancreatic cancer cells to death by a caspase-independent process involving LMP and oxidative stress which is protected from by NAC. PB282 however undergoes a caspase-dependent death

Translational PK-PD modelling of molecular target modulation for the AMPA receptor positive allosteric modulator Org 26576.

PubMed

Bursi, Roberta; Erdemli, Gul; Campbell, Robert; Hutmacher, Matthew M; Kerbusch, Thomas; Spanswick, David; Jeggo, Ross; Nations, Kari R; Dogterom, Peter; Schipper, Jacques; Shahid, Mohammed

2011-12-01

The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor potentiator Org 26576 represents an interesting pharmacological tool to evaluate the utility of glutamatergic enhancement towards the treatment of psychiatric disorders. In this study, a rat-human translational pharmacokinetic-pharmacodynamic (PK-PD) model of AMPA receptor modulation was used to predict human target engagement and inform dose selection in efficacy clinical trials. Modelling and simulation was applied to rat plasma and cerebrospinal fluid (CSF) pharmacokinetic and pharmacodynamic measurements to identify a target concentration (EC(80)) for AMPA receptor modulation. Human plasma pharmacokinetics was determined from 33 healthy volunteers and eight major depressive disorder patients. From four out of these eight patients, CSF PK was also determined. Simulations of human CSF levels were performed for several doses of Org 26576. Org 26576 (0.1-10 mg/kg, i.v.) potentiated rat hippocampal AMPA receptor responses in an exposure-dependant manner. The rat plasma and CSF PK data were fitted by one-compartment model each. The rat CSF PK-PD model yielded an EC(80) value of 593 ng/ml (90% confidence interval 406.8, 1,264.1). The human plasma and CSF PK data were simultaneously well described by a two-compartment model. Simulations showed that in humans at 100 mg QD, CSF levels of Org 26576 would exceed the EC(80) target concentration for about 2 h and that 400 mg BID would engage AMPA receptors for 24 h. The modelling approach provided useful insight on the likely human dose-molecular target engagement relationship for Org 26576. Based on the current analysis, 100 and 400 mg BID would be suitable to provide 'phasic' and 'continuous' AMPA receptor engagement, respectively.

Modeling activity and target-dependent developmental cell death of mouse retinal ganglion cells ex vivo.

PubMed

Voyatzis, Sylvie; Muzerelle, Aude; Gaspar, Patricia; Nicol, Xavier

2012-01-01

Programmed cell death is widespread during the development of the central nervous system and serves multiple purposes including the establishment of neural connections. In the mouse retina a substantial reduction of retinal ganglion cells (RGCs) occurs during the first postnatal week, coinciding with the formation of retinotopic maps in the superior colliculus (SC). We previously established a retino-collicular culture preparation which recapitulates the progressive topographic ordering of RGC projections during early post-natal life. Here, we questioned whether this model could also be suitable to examine the mechanisms underlying developmental cell death of RGCs. Brn3a was used as a marker of the RGCs. A developmental decline in the number of Brn3a-immunolabelled neurons was found in the retinal explant with a timing that paralleled that observed in vivo. In contrast, the density of photoreceptors or of starburst amacrine cells increased, mimicking the evolution of these cell populations in vivo. Blockade of neural activity with tetrodotoxin increased the number of surviving Brn3a-labelled neurons in the retinal explant, as did the increase in target availability when one retinal explant was confronted with 2 or 4 collicular slices. Thus, this ex vivo model reproduces the developmental reduction of RGCs and recapitulates its regulation by neural activity and target availability. It therefore offers a simple way to analyze developmental cell death in this classic system. Using this model, we show that ephrin-A signaling does not participate to the regulation of the Brn3a population size in the retina, indicating that eprhin-A-mediated elimination of exuberant projections does not involve developmental cell death.

High Throughput Sequencing Identifies MicroRNAs Mediating α-Synuclein Toxicity by Targeting Neuroactive-Ligand Receptor Interaction Pathway in Early Stage of Drosophila Parkinson's Disease Model.

PubMed

Kong, Yan; Liang, Xijun; Liu, Lin; Zhang, Dongdong; Wan, Chao; Gan, Zhenji; Yuan, Liudi

2015-01-01

Parkinson's disease (PD) is a prevalent neurodegenerative disorder with pathological features including death of dopaminergic neurons in the substantia nigra and intraneuronal accumulations of Lewy bodies. As the main component of Lewy bodies, α-synuclein is implicated in PD pathogenesis by aggregation into insoluble filaments. However, the detailed mechanisms underlying α-synuclein induced neurotoxicity in PD are still elusive. MicroRNAs are ~20nt small RNA molecules that fine-tune gene expression at posttranscriptional level. A plethora of miRNAs have been found to be dysregulated in the brain and blood cells of PD patients. Nevertheless, the detailed mechanisms and their in vivo functions in PD still need further investigation. By using Drosophila PD model expressing α-synuclein A30P, we examined brain miRNA expression with high-throughput small RNA sequencing technology. We found that five miRNAs (dme-miR-133-3p, dme-miR-137-3p, dme-miR-13b-3p, dme-miR-932-5p, dme-miR-1008-5p) were upregulated in PD flies. Among them, miR-13b, miR-133, miR-137 are brain enriched and highly conserved from Drosophila to humans. KEGG pathway analysis using DIANA miR-Path demonstrated that neuroactive-ligand receptor interaction pathway was most likely affected by these miRNAs. Interestingly, miR-137 was predicted to regulate most of the identified targets in this pathway, including dopamine receptor (DopR, D2R), γ-aminobutyric acid (GABA) receptor (GABA-B-R1, GABA-B-R3) and N-methyl-D-aspartate (NMDA) receptor (Nmdar2). The validation experiments showed that the expression of miR-137 and its targets was negatively correlated in PD flies. Further experiments using luciferase reporter assay confirmed that miR-137 could act on specific sites in 3' UTR region of D2R, Nmdar2 and GABA-B-R3, which downregulated significantly in PD flies. Collectively, our findings indicate that α-synuclein could induce the dysregulation of miRNAs, which target neuroactive ligand-receptor interaction

MIR506 induces autophagy-related cell death in pancreatic cancer cells by targeting the STAT3 pathway.

PubMed

Sun, Longhao; Hu, Limei; Cogdell, David; Lu, Li; Gao, Chao; Tian, Weijun; Zhang, Zhixiang; Kang, Ya'an; Fleming, Jason B; Zhang, Wei

2017-04-03

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive and lethal cancer. The role of autophagy in the pathobiology of PDAC is intricate, with opposing functions manifested in different cellular contexts. MIR506 functions as a tumor suppressor in many cancer types through the regulation of multiple pathways. In this study, we hypothesized that MIR506 exerted a tumor suppression function in PDAC by inducing autophagy-related cell death. Our results provided evidence that downregulation of MIR506 expression was associated with disease progression in human PDAC. MIR506 triggered autophagic flux in PDAC cells, which led to autophagy-related cell death through direct targeting of the STAT3 (signal transducer and activator of transcription 3)-BCL2-BECN1 axis. Silencing and inhibiting STAT3 recapitulated the effects of MIR506, whereas forced expression of STAT3 abrogated the effects of MIR506. We propose that the apoptosis-inhibitory protein BCL2, which also inhibits induction of autophagy by blocking BECN1, was inhibited by MIR506 through targeting STAT3, thus augmenting BECN1 and promoting autophagy-related cell death. Silencing BECN1 and overexpression of BCL2 abrogated the effects of MIR506. These findings expand the known mechanisms of MIR506-mediated tumor suppression to activation of autophagy-related cell death and suggest a strategy for using MIR506 as an anti-STAT3 approach to PDAC treatment.

Tissue factor is an angiogenic-specific receptor for factor VII-targeted immunotherapy and photodynamic therapy.

PubMed

Hu, Zhiwei; Cheng, Jijun; Xu, Jie; Ruf, Wolfram; Lockwood, Charles J

2017-02-01

Identification of target molecules specific for angiogenic vascular endothelial cells (VEC), the inner layer of pathological neovasculature, is critical for discovery and development of neovascular-targeting therapy for angiogenesis-dependent human diseases, notably cancer, macular degeneration and endometriosis, in which vascular endothelial growth factor (VEGF) plays a central pathophysiological role. Using VEGF-stimulated vascular endothelial cells (VECs) isolated from microvessels, venous and arterial blood vessels as in vitro angiogenic models and unstimulated VECs as a quiescent VEC model, we examined the expression of tissue factor (TF), a membrane-bound receptor on the angiogenic VEC models compared with quiescent VEC controls. We found that TF is specifically expressed on angiogenic VECs in a time-dependent manner in microvessels, venous and arterial vessels. TF-targeted therapeutic agents, including factor VII (fVII)-IgG1 Fc and fVII-conjugated photosensitizer, can selectively bind angiogenic VECs, but not the quiescent VECs. Moreover, fVII-targeted photodynamic therapy can selectively and completely eradicate angiogenic VECs. We conclude that TF is an angiogenic-specific receptor and the target molecule for fVII-targeted therapeutics. This study supports clinical trials of TF-targeted therapeutics for the treatment of angiogenesis-dependent diseases such as cancer, macular degeneration and endometriosis.

[Novel Anticancer Strategy Targeting Switch Mechanisms in Two Types of Cell Death: Necrosis and Apoptosis].

PubMed

Sato, Akira

2017-01-01

 Two types of cell death, necrosis and apoptosis, are defined in terms of cell death morphological features. We have been studying the mechanisms by which cell death processes are switched during the treatment of mouse tumor FM3A with anticancer, 5-fluoro-2'-deoxyuridine (FUdR): it induces original clone F28-7 to necrosis, but its sub-clone F28-7-A to apoptosis. We identified several such switch regulators of cell death: heat shock protein 90 (HSP90), lamin-B1, cytokeratin-19, and activating transcription factor 3 (ATF3), by using transcriptomic, proteomic analyses and siRNA screening. For example, the inhibition of HSP90 by its inhibitor geldanamycin in F28-7 caused a shift from necrosis to apoptosis. We also observed that the knockdown of lamin-B1, cytokeratin-19, or ATF3 expression in F28-7 resulted in a shift from necrosis to apoptosis. Recently, we used microRNA (miRNA, miR) microarray analyses to investigate the miRNA expression profiles in these sister cells. The miR-351 and miR-743a were expressed at higher levels in F28-7-A than in F28-7. Higher expression of miR-351 or miR-743a in F28-7, induced by transfecting the miR mimics, resulted in a switch of cell death mode: necrosis to apoptosis. Furthermore, transfection of an miR-351 inhibitor into F28-7-A resulted in morphological changes, and mode of cell death from apoptosis to necrosis. These findings suggest that the identified cell death regulators may have key roles in switching cell death mode. Possible mechanisms involving cell death regulators in the switch of necrosis or apoptosis are discussed. We propose a novel anticancer strategy targeting the switch regulators of necrosis or apoptosis.

The immunomodulatory properties of the CD5 lymphocyte receptor in health and disease

PubMed Central

Soldevila, Gloria; Raman, Chander; Lozano, Francisco

2011-01-01

Summary CD5 is a scavenger-like receptor expressed in association with the antigen-specific receptors on T and B-1a lymphocytes. Recent studies reveal a broader biology for CD5 that includes its role as regulator of cell death and as a receptor for pathogen associated molecular patterns, in addition to its previously described function as an inhibitory receptor. These findings shed new light into the mechanistic role of CD5 in leukemias and effector cells to exogenous (infectious) or endogenous (autoimmune, tumoral) antigens. The newly identified properties make this receptor a potential candidate to be targeted for therapeutic intervention as well as immune modulation. This review describes the current knowledge on the function of CD5 as an immunomodulatory receptor both in health and disease. PMID:21482089

Tumor-targeting peptides from combinatorial libraries.

PubMed

Liu, Ruiwu; Li, Xiaocen; Xiao, Wenwu; Lam, Kit S

2017-02-01

Cancer is one of the major and leading causes of death worldwide. Two of the greatest challenges in fighting cancer are early detection and effective treatments with no or minimum side effects. Widespread use of targeted therapies and molecular imaging in clinics requires high affinity, tumor-specific agents as effective targeting vehicles to deliver therapeutics and imaging probes to the primary or metastatic tumor sites. Combinatorial libraries such as phage-display and one-bead one-compound (OBOC) peptide libraries are powerful approaches in discovering tumor-targeting peptides. This review gives an overview of different combinatorial library technologies that have been used for the discovery of tumor-targeting peptides. Examples of tumor-targeting peptides identified from each combinatorial library method will be discussed. Published tumor-targeting peptide ligands and their applications will also be summarized by the combinatorial library methods and their corresponding binding receptors. Copyright © 2017. Published by Elsevier B.V.

Over-expression of angiotensin II type 2 receptor gene induces cell death in lung adenocarcinoma cells.

PubMed

Pickel, Lara; Matsuzuka, Takaya; Doi, Chiyo; Ayuzawa, Rie; Maurya, Dharmendra Kumar; Xie, Sheng-Xue; Berkland, Cory; Tamura, Masaaki

2010-02-01

The endogenous angiotensin II (Ang II) type 2 receptor (AT 2) has been shown to mediate apoptosis in cardiovascular tissues. Thus, the aim of this study was to explore the anti-cancer effect of AT 2 over-expression on lung adenocarcinoma cells in vitro using adenoviral (Ad), FuGENE, and nanoparticle vectors. All three gene transfection methods efficiently transfected AT 2 cDNA into lung cancer cells but caused minimal gene transfection in normal lung epithelial cells. Ad-AT 2 significantly attenuated multiple human lung cancer cell growth (A549 and H358) as compared to the control viral vector, Ad-LacZ, when cell viability was examined by direct cell count. Examination of annexin V by flow cytometry revealed the activation of the apoptotic pathway via AT 2 over-expression. Western Blot analysis confirmed the activation of caspase-3. Similarly, poly (lactide-co-glycolic acid) (PLGA) biodegradable nanoparticles encapsulated AT 2 plasmid DNA were shown to be effectively taken up into the lung cancer cell. Nanoparticle-based AT 2 gene transfection markedly increased AT 2 expression and resultant cell death in A549 cells. These results indicate that AT 2 over-expression effectively attenuates growth of lung adenocarcinoma cells through intrinsic apoptosis. Our results also suggest that PLGA nanoparticles can be used as an efficient gene delivery vector for lung adenocarcinoma targeted therapy.

Hemangiosarcoma and its cancer stem cell subpopulation are effectively killed by a toxin targeted through epidermal growth factor and urokinase receptors.

PubMed

Schappa, Jill T; Frantz, Aric M; Gorden, Brandi H; Dickerson, Erin B; Vallera, Daniel A; Modiano, Jaime F

2013-10-15

Targeted toxins have the potential to overcome intrinsic or acquired resistance of cancer cells to conventional cytotoxic agents. Here, we hypothesized that EGFuPA-toxin, a bispecific ligand-targeted toxin (BLT) consisting of a deimmunized Pseudomonas exotoxin (PE) conjugated to epidermal growth factor and urokinase, would efficiently target and kill cells derived from canine hemangiosarcoma (HSA), a highly chemotherapy resistant tumor, as well as cultured hemangiospheres, used as a surrogate for cancer stem cells (CSC). EGFuPA-toxin showed cytotoxicity in four HSA cell lines (Emma, Frog, DD-1 and SB) at a concentration of ≤100 nM, and the cytotoxicity was dependent on specific ligand-receptor interactions. Monospecific targeted toxins also killed these chemoresistant cells; in this case, a "threshold" level of EGFR expression appeared to be required to make cells sensitive to the monospecific EGF-toxin, but not to the monospecific uPA-toxin. The IC₅₀ of CSCs was higher by approximately two orders of magnitude as compared to non-CSCs, but these cells were still sensitive to EGFuPA-toxin at nanomolar (i.e., pharmacologically relevant) concentrations, and when targeted by EGFuPA-toxin, resulted in death of the entire cell population. Taken together, our results support the use of these toxins to treat chemoresistant tumors such as sarcomas, including those that conform to the CSC model. Our results also support the use of companion animals with cancer for further translational development of these cytotoxic molecules. Copyright © 2013 UICC.

Melatonin ameliorates oxidative stress, modulates death receptor pathway proteins, and protects the rat cerebrum against bisphenol-A-induced apoptosis.

PubMed

El-Missiry, Mohamed A; Othman, Azza I; Al-Abdan, Monera A; El-Sayed, Aml A

2014-12-15

Epidemiological reports have indicated a correlation between the increasing of bisphenol-A (BPA) levels in the environment and the incidence of neurodegenerative diseases. In the present study, the protective effect of melatonin on oxidative stress and the death receptor apoptotic proteins in the cerebrum of the bisphenol-A-treated rats were examined. Adult male rats were orally administered melatonin (10mg/kg bw) concurrently with BPA (50mg/kg bw) 3 days a week for 6 weeks. BPA exposure resulted in significant elevations of oxidative stress, as evidenced by the increased malondialdehyde level and the decreased glutathione level and superoxide dismutase activity in the cerebrum. BPA caused an upregulation of p53 and CD95-Fas and activation of capsases-3 and 8, resulting in cerebral cell apoptosis. Melatonin significantly attenuated the BPA-evoked brain oxidative stress, modulated apoptotic-regulating proteins and protected against apoptosis. These data suggest that melatonin modulated important steps in the death receptor apoptotic pathway which likely related to its redox control properties. Melatonin is a promising pharmacological agent for preventing the potential neurotoxicity of BPA following occupational or environmental exposures. Copyright © 2014 Elsevier B.V. All rights reserved.

TAM receptors Tyro3 and Mer as novel targets in colorectal cancer.

PubMed

Schmitz, Robin; Valls, Aida Freire; Yerbes, Rosario; von Richter, Sophie; Kahlert, Christoph; Loges, Sonja; Weitz, Jürgen; Schneider, Martin; Ruiz de Almodovar, Carmen; Ulrich, Alexis; Schmidt, Thomas

2016-08-30

CRC remains the third most common cancer worldwide with a high 5-year mortality rate in advanced cases. Combined with chemotherapy, targeted therapy is an additional treatment option. However as CRC still escapes targeted therapy the vigorous search for new targets is warranted to increase patients´ overall survival. In this study we describe a new role for Gas6/protein S-TAM receptor interaction in CRC. Gas6, expressed by tumor-infiltrating M2-like macrophages, enhances malignant properties of tumor cells including proliferation, invasion and colony formation. Upon chemotherapy macrophages increase Gas6 synthesis, which significantly attenuates the cytotoxic effect of 5-FU chemotherapy on tumor cells. The anti-coagulant protein S has similar effects as Gas6.In CRC patient samples Tyro3 was overexpressed within the tumor. In-vitro inhibition of Tyro3 and Mer reduces tumor cell proliferation and sensitizes tumor cells to chemotherapy. Moreover high expression of Tyro3 and Mer in tumor tissue significantly shortens CRC patients´ survival. Various in vitro models were used to investigate the role of Gas6 and its TAM receptors in human CRC cells, by stimulation (rhGas6) and knockdown (siRNA) of Axl, Tyro3 and Mer. In terms of a translational research, we additionally performed an expression analysis in human CRC tissue and analyzed the medical record of these patients. Tyro3 and Mer represent novel therapeutic targets in CRC and warrant further preclinical and clinical investigation in the future.

Detection of Sendai virus receptor, the ganglioside GDla, in target tissue (mouse lung)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markwell, M.A.K.; Sato, E.

1986-05-01

Previously the authors had shown that the gangliosides GDla, GTlb, and GQlb derived from brain function as receptors for the paramyxovirus Sendai virus by their ability to induce infection when incubated with receptor-deficient cells. Analyses of MDBK, HeLa, and MDCK cells in culture demonstrated that these putative receptors were present in host cells in the quantities required for infection. The primary site of infection for Sendai virus in the whole animal is the respiratory tract, culminating in the lung. Therefore, the ganglioside content of this target organ was analyzed to determine the endogenous receptor population available to Sendai virus. Themore » total ganglioside fraction of lung was resolved into individual species by HPTLC. Gangliosides of the gangliotetraose series were identified by the specific binding of /sup 125/I-labeled tetanus and cholera toxins before and after exposure with sialidase. In this manner one of the major resorcinol-positive bands was identified as GDla. Evidence of the more complex ganglioside receptors for Sendai virus was also seen.« less

Non-synaptic receptors and transporters involved in brain functions and targets of drug treatment

PubMed Central

Vizi, ES; Fekete, A; Karoly, R; Mike, A

2010-01-01

Beyond direct synaptic communication, neurons are able to talk to each other without making synapses. They are able to send chemical messages by means of diffusion to target cells via the extracellular space, provided that the target neurons are equipped with high-affinity receptors. While synaptic transmission is responsible for the ‘what’ of brain function, the ‘how’ of brain function (mood, attention, level of arousal, general excitability, etc.) is mainly controlled non-synaptically using the extracellular space as communication channel. It is principally the ‘how’ that can be modulated by medicine. In this paper, we discuss different forms of non-synaptic transmission, localized spillover of synaptic transmitters, local presynaptic modulation and tonic influence of ambient transmitter levels on the activity of vast neuronal populations. We consider different aspects of non-synaptic transmission, such as synaptic–extrasynaptic receptor trafficking, neuron–glia communication and retrograde signalling. We review structural and functional aspects of non-synaptic transmission, including (i) anatomical arrangement of non-synaptic release sites, receptors and transporters, (ii) intravesicular, intra- and extracellular concentrations of neurotransmitters, as well as the spatiotemporal pattern of transmitter diffusion. We propose that an effective general strategy for efficient pharmacological intervention could include the identification of specific non-synaptic targets and the subsequent development of selective pharmacological tools to influence them. PMID:20136842

The challenges of modulating the 'rest and digest' system: acetylcholine receptors as drug targets.

PubMed

VanPatten, Sonya; Al-Abed, Yousef

2017-01-01

Acetylcholine, a major neurotransmitter of the parasympathetic and sympathetic nervous systems, was discovered in the early 1900s. Over the years, researchers have revealed much about its regulation, properties of its receptors and features of the downstream signaling that influence its terminal effects. The acetylcholine system, traditionally associated with neuromuscular communication, is now known to play a crucial part in modulation of the immune system and other 'rest and digest' effects. Recent research seeks to elucidate the system's role in brain functions including cognition, sleep, arousal, motivation, reward and pain. We highlight clinically approved and experimental drugs that modulate the acetylcholine receptors. The complexities in targeting the acetylcholine receptors are vast and finding future indications for drug development associated with specific acetylcholine receptors remains a challenge. Copyright © 2016 Elsevier Ltd. All rights reserved.

A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, So Jung; Park, Young Jun; Shin, Ji Hyun

2011-05-13

Highlights: {yields} We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. {yields} Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. {yields} Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. {yields} Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactivemore » chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.« less

Emerging strategies for EphA2 receptor targeting for cancer therapeutics

PubMed Central

Tandon, Manish; Vemula, Sai Vikram; Mittal, Suresh K.

2010-01-01

Importance of the field High mortality rates with cancers warrant further development of earlier diagnostics and better treatment strategies. Membrane-bound hepatocellular receptor tyrosine kinase class A2 (EphA2) is overexpressed in breast, prostate, urinary bladder, skin, lung, ovary and brain cancers. Areas covered in this review This review describes EphA2 overexpression in cancers, its signaling mechanisms and strategies to target its deregulation. What will the reader will gain High EphA2 expression in cancer cells is correlated to a poor prognosis associated with recurrence due to enhanced metastasis. Interaction of the EphA2 receptor with its ligand (e.g., EphrinA1) triggers events that are deregulated and implicated in carcinogenesis. Both EphrinA1-independent oncogenic activity and EphrinA1-dependent tumor suppressor roles for EphA2 are described. Molecular interactions of EphA2 with signaling proteins are associated with the modulation of cytoskeleton dynamics, cell adhesion, proliferation, differentiation and metastasis. The deregulated signaling by EphA2 and its involvement in oncogenesis provide multiple avenues for the rational design of intervention approaches. Take home message EphA2 has been tested as a drug target using multiple approaches such as agonist antibodies, RNA interference, immunotherapy, virus vectors-mediated gene transfer, small molecule inhibitors and nanoparticles. With over a decade of research, encouraging results with successful targeting of EphA2 expression in various pre-clinical cancer models necessitate further studies. PMID:21142802

Peroxisome Proliferator-Activated Receptor Subtype- and Cell-Type-Specific Activation of Genomic Target Genes upon Adenoviral Transgene Delivery

PubMed Central

Nielsen, Ronni; Grøntved, Lars; Stunnenberg, Hendrik G.; Mandrup, Susanne

2006-01-01

Investigations of the molecular events involved in activation of genomic target genes by peroxisome proliferator-activated receptors (PPARs) have been hampered by the inability to establish a clean on/off state of the receptor in living cells. Here we show that the combination of adenoviral delivery and chromatin immunoprecipitation (ChIP) is ideal for dissecting these mechanisms. Adenoviral delivery of PPARs leads to a rapid and synchronous expression of the PPAR subtypes, establishment of transcriptional active complexes at genomic loci, and immediate activation of even silent target genes. We demonstrate that PPARγ2 possesses considerable ligand-dependent as well as independent transactivation potential and that agonists increase the occupancy of PPARγ2/retinoid X receptor at PPAR response elements. Intriguingly, by direct comparison of the PPARs (α, γ, and β/δ), we show that the subtypes have very different abilities to gain access to target sites and that in general the genomic occupancy correlates with the ability to activate the corresponding target gene. In addition, the specificity and potency of activation by PPAR subtypes are highly dependent on the cell type. Thus, PPAR subtype-specific activation of genomic target genes involves an intricate interplay between the properties of the subtype- and cell-type-specific settings at the individual target loci. PMID:16847324

The p75 neurotrophin receptor: at the crossroad of neural repair and death

PubMed Central

Meeker, Rick B.; Williams, Kimberly S.

2015-01-01

The strong repair and pro-survival functions of neurotrophins at their primary receptors, TrkA, TrkB and TrkC, have made them attractive candidates for treatment of nervous system injury and disease. However, difficulties with the clinical implementation of neurotrophin therapies have prompted the search for treatments that are stable, easier to deliver and allow more precise regulation of neurotrophin actions. Recently, the p75 neurotrophin receptor (p75NTR) has emerged as a potential target for pharmacological control of neurotrophin activity, supported in part by studies demonstrating 1) regulation of neural plasticity in the mature nervous system, 2) promotion of adult neurogenesis and 3) increased expression in neurons, macrophages, microglia, astrocytes and/or Schwann cells in response to injury and neurodegenerative diseases. Although the receptor has no intrinsic catalytic activity it interacts with and modulates the function of TrkA, TrkB, and TrkC, as well as sortilin and the Nogo receptor. This provides substantial cellular and molecular diversity for regulation of neuron survival, neurogenesis, immune responses and processes that support neural function. Upregulation of the p75NTR under pathological conditions places the receptor in a key position to control numerous processes necessary for nervous system recovery. Support for this possibility has come from recent studies showing that small, non-peptide p75NTR ligands can selectively modify pro-survival and repair functions. While a great deal remains to be discovered about the wide ranging functions of the p75NTR, studies summarized in this review highlight the immense potential for development of novel neuroprotective and neurorestorative therapies. PMID:26109945

Efficient Receptor Mediated siRNA Delivery in Vitro by Folic Acid Targeted Pentablock Copolymer-Based Micelleplexes.

PubMed

Lehner, Roman; Liu, Kegang; Wang, Xueya; Hunziker, Patrick

2017-08-14

Novel, biocompatible polyplexes, based on the combination of cationic pentablock copolymers with folic acid functionalized copolymers, were designed and developed for target-specific siRNA delivery. The resulting micelleplexes spontaneously formed polymeric micelles with a hydrophobic core surrounded directly by a cationic poly-2-(4-aminobutyl)-oxazole (PABOXA) and subsequently shielded by hydrophilic poly-2-methyl-oxazole (PMOXA) layer. The described micelleplexes form highly stable particles even in complete serum after 24 h compared with the highly cationic polymer PEI, which show aggregate formation in serum containing buffer solution. Targeted siRNA delivery and gene knockdown could be shown using green fluorescent protein (GFP) expressing HeLa cells, resulting in ∼31% and ∼8% suppression of the expression of GFP for targeted and nontargeted micelleplexes, respectively. Comparison studies of folic-receptor positive HeLa cells with normal folic-receptor-negative HEK293 cells revealed involvement of receptor mediated cellular uptake of fluorescently labeled siRNA. The new designed nanocarrier showed no cytotoxicity, having a potential application. The presented concept of shielding a nucleic-acid complexing cationic chains with a stealth layer and combining it with receptor ligand overcomes typical problems with undesired protein and cell interactions in delivery of nucleic acids using polymeric systems, opening new doors for application if RNA inhibition in the organism.

Survival Improvement in Human Retinal Pigment Epithelial Cells via Fas Receptor Targeting by miR-374a.

PubMed

Tasharrofi, Nooshin; Kouhkan, Fatemeh; Soleimani, Masoud; Soheili, Zahra-Sheila; Kabiri, Mahboubeh; Mahmoudi Saber, Mohaddeseh; Dorkoosh, Farid Abedin

2017-12-01

Oxidative conditions of the eye could contribute to retinal cells loss through activating the Fas-L/Fas pathway. This phenomenon is one of the leading causes of some ocular diseases like age-related macular degeneration (AMD). By targeting proteins at their mRNA level, microRNAs (miRNAs) can regulate gene expression and cell function. The aim of the present study is to investigate Fas targeting by miR-374a and find whether it can inhibit Fas-mediated apoptosis in primary human retinal pigment epithelial (RPE) cells under oxidative stress. So, the primary human RPE cells were transfected with pre-miR-374a pLEX construct using polymeric carrier and were exposed to H 2 O 2 (200 μM) as an oxidant agent for induction of Fas expression. Fas expression at mRNA and protein level was evaluated by quantitative real-time PCR and Western blot analysis, respectively. These results revealed that miR-374a could prevent Fas upregulation under oxidative conditions. Moreover, Luciferase activity assay confirmed that Fas could be a direct target of miR-374a. The cell viability studies demonstrated that caspase-3 activity was negligible in miR-374a treated cells compared to the controls. Our data suggest miR-374a is a negative regulator of Fas death receptor which is able to enhance the cell survival and protect RPE cells against oxidative conditions. J. Cell. Biochem. 118: 4854-4861, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Prostate-targeted biodegradable nanoparticles loaded with androgen receptor silencing constructs eradicate xenograft tumors in mice

PubMed Central

Yang, Jun; Xie, Sheng-Xue; Huang, Yiling; Ling, Min; Liu, Jihong; Ran, Yali; Wang, Yanlin; Thrasher, J Brantley; Berkland, Cory; Li, Benyi

2012-01-01

Background Prostate cancer is the major cause of cancer death in men and the androgen receptor (AR) has been shown to play a critical role in the progression of the disease. Our previous reports showed that knocking down the expression of the AR gene using a siRNA-based approach in prostate cancer cells led to apoptotic cell death and xenograft tumor eradication. In this study, we utilized a biodegradable nanoparticle to deliver the therapeutic AR shRNA construct specifically to prostate cancer cells. Materials & methods The biodegradable nanoparticles were fabricated using a poly(dl-lactic-co-glycolic acid) polymer and the AR shRNA constructs were loaded inside the particles. The surface of the nanoparticles were then conjugated with prostate-specific membrane antigen aptamer A10 for prostate cancer cell-specific targeting. Results A10-conjugation largely enhanced cellular uptake of nanoparticles in both cell culture- and xenograft-based models. The efficacy of AR shRNA encapsulated in nanoparticles on AR gene silencing was confirmed in PC-3/AR-derived xenografts in nude mice. The therapeutic property of A10-conjugated AR shRNA-loaded nanoparticles was evaluated in xenograft models with different prostate cancer cell lines: 22RV1, LAPC-4 and LNCaP. Upon two injections of the AR shRNA-loaded nanoparticles, rapid tumor regression was observed over 2 weeks. Consistent with previous reports, A10 aptamer conjugation significantly enhanced xenograft tumor regression compared with nonconjugated nanoparticles. Discussion These data demonstrated that tissue-specific delivery of AR shRNA using a biodegradable nanoparticle approach represents a novel therapy for life-threatening prostate cancers. PMID:22583574

Rational drug design and synthesis of molecules targeting the angiotensin II type 1 and type 2 receptors.

PubMed

Kellici, Tahsin F; Tzakos, Andreas G; Mavromoustakos, Thomas

2015-03-02

The angiotensin II (Ang II) type 1 and type 2 receptors (AT1R and AT2R) orchestrate an array of biological processes that regulate human health. Aberrant function of these receptors triggers pathophysiological responses that can ultimately lead to death. Therefore, it is important to design and synthesize compounds that affect beneficially these two receptors. Cardiovascular disease, which is attributed to the overactivation of the vasoactive peptide hormone Αng II, can now be treated with commercial AT1R antagonists. Herein, recent achievements in rational drug design and synthesis of molecules acting on the two AT receptors are reviewed. Quantitative structure activity relationships (QSAR) and molecular modeling on the two receptors aim to assist the search for new active compounds. As AT1R and AT2R are GPCRs and drug action is localized in the transmembrane region the role of membrane bilayers is exploited. The future perspectives in this field are outlined. Tremendous progress in the field is expected if the two receptors are crystallized, as this will assist the structure based screening of the chemical space and lead to new potent therapeutic agents in cardiovascular and other diseases.

Targeting transferrin receptors at the blood-brain barrier improves the uptake of immunoliposomes and subsequent cargo transport into the brain parenchyma.

PubMed

Johnsen, Kasper Bendix; Burkhart, Annette; Melander, Fredrik; Kempen, Paul Joseph; Vejlebo, Jonas Bruun; Siupka, Piotr; Nielsen, Morten Schallburg; Andresen, Thomas Lars; Moos, Torben

2017-09-04

Drug delivery to the brain is hampered by the presence of the blood-brain barrier, which excludes most molecules from freely diffusing into the brain, and tightly regulates the active transport mechanisms that ensure sufficient delivery of nutrients to the brain parenchyma. Harnessing the possibility of delivering neuroactive drugs by way of receptors already present on the brain endothelium has been of interest for many years. The transferrin receptor is of special interest since its expression is limited to the endothelium of the brain as opposed to peripheral endothelium. Here, we investigate the possibility of delivering immunoliposomes and their encapsulated cargo to the brain via targeting of the transferrin receptor. We find that transferrin receptor-targeting increases the association between the immunoliposomes and primary endothelial cells in vitro, but that this does not correlate with increased cargo transcytosis. Furthermore, we show that the transferrin receptor-targeted immunoliposomes accumulate along the microvessels of the brains of rats, but find no evidence for transcytosis of the immunoliposome. Conversely, the increased accumulation correlated both with increased cargo uptake in the brain endothelium and subsequent cargo transport into the brain. These findings suggest that transferrin receptor-targeting is a relevant strategy of increasing drug exposure to the brain.

Programmed death-1 & its ligands: promising targets for cancer immunotherapy.

PubMed

Shrimali, Rajeev K; Janik, John E; Abu-Eid, Rasha; Mkrtichyan, Mikayel; Khleif, Samir N

2015-01-01

Novel strategies for cancer treatment involving blockade of immune inhibitors have shown significant progress toward understanding the molecular mechanism of tumor immune evasion. The preclinical findings and clinical responses associated with programmed death-1 (PD-1) and PD-ligand pathway blockade seem promising, making these targets highly sought for cancer immunotherapy. In fact, the anti-PD-1 antibodies, pembrolizumab and nivolumab, were recently approved by the US FDA for the treatment of unresectable and metastatic melanoma resistant to anticytotoxic T-lymphocyte antigen-4 antibody (ipilimumab) and BRAF inhibitor. Here, we discuss strategies of combining PD-1/PD-ligand interaction inhibitors with other immune checkpoint modulators and standard-of-care therapy to break immune tolerance and induce a potent antitumor activity, which is currently a research area of key scientific pursuit.

N-Methyl-d-Aspartate (NMDA) Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection

PubMed Central

Costa, Vivian V.; Del Sarto, Juliana L.; Rocha, Rebeca F.; Silva, Flavia R.; Doria, Juliana G.; Olmo, Isabella G.; Marques, Rafael E.; Queiroz-Junior, Celso M.; Foureaux, Giselle; Araújo, Julia Maria S.; Cramer, Allysson; Real, Ana Luíza C. V.; Ribeiro, Lucas S.; Sardi, Silvia I.; Ferreira, Anderson J.; Machado, Fabiana S.; de Oliveira, Antônio C.; Teixeira, Antônio L.; Nakaya, Helder I.; Souza, Danielle G.

2017-01-01

ABSTRACT Zika virus (ZIKV) infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N-methyl-d-aspartate receptor (NMDAR)-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801), agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP) induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration. PMID:28442607

UV-Induced cell death in plants.

PubMed

Nawkar, Ganesh M; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

2013-01-14

Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400-700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280-320 nm) and UV-A (320-390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD).

Purinergic receptors and neglected tropical diseases: why ignore purinergic signaling in the search for new molecular targets?

PubMed

Pacheco, P A F; Dantas, L P; Ferreira, L G B; Faria, Robson Xavier

2018-06-07

Purinergic receptors are widespread in the human organism and are involved in several physiological functions like neurotransmission, nociception, platelet aggregation, etc. In the immune system, they may regulate the expression and release of pro-inflammatory factors as well as the activation and death of several cell types. It is already described the participation of some purinergic receptors in the inflammation and pathological processes, such as a few neglected tropical diseases (NTDs) which affect more than 1 billion people in the world. Although the high social influence those diseases represent endemic countries, most of them do not have an efficient, safe or affordable drug treatment. In that way, this review aims to discuss the current literature involving purinergic receptor and immune response to NTDs pathogens, which may contribute in the search for new therapeutic possibilities.

Activation of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) induces cell death through MAPK-dependent mechanism in osteoblastic cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Sung Hun; Yoo, Chong Il; Medical Research Institute, College of Medicine, Pusan National University, Pusan, 602-739

2006-09-01

The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPAR{gamma} agonists in osteoblastic cells. Ciglitazone and troglitazone, PPAR{gamma} agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPAR{alpha} agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPAR{gamma} antagonist GW9662. Ciglitazone treatmentmore » caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis.« less

Intravenous siRNA of brain cancer with receptor targeting and avidin-biotin technology.

PubMed

Xia, Chun-Fang; Zhang, Yufeng; Zhang, Yun; Boado, Ruben J; Pardridge, William M

2007-12-01

The effective delivery of short interfering RNA (siRNA) to brain following intravenous administration requires the development of a delivery system for transport of the siRNA across the brain capillary endothelial wall, which forms the blood-brain barrier in vivo. siRNA was delivered to brain in vivo with the combined use of a receptor-specific monoclonal antibody delivery system, and avidin-biotin technology. The siRNA was mono-biotinylated on either terminus of the sense strand, in parallel with the production of a conjugate of the targeting MAb and streptavidin. Rat glial cells (C6 or RG-2) were permanently transfected with the luciferase gene, and implanted in the brain of adult rats. Following the formation of intra-cranial tumors, the rats were treated with a single intravenous injection of 270 microg/kg of biotinylated siRNA attached to a transferrin receptor antibody via a biotin-streptavidin linker. The intravenous administration of the siRNA caused a 69-81% decrease in luciferase gene expression in the intracranial brain cancer in vivo. Brain delivery of siRNA following intravenous administration is possible with siRNAs that are targeted to brain with the combined use of receptor specific antibody delivery systems and avidin-biotin technology.

Targeting GLP-1 receptor trafficking to improve agonist efficacy.

PubMed

Jones, Ben; Buenaventura, Teresa; Kanda, Nisha; Chabosseau, Pauline; Owen, Bryn M; Scott, Rebecca; Goldin, Robert; Angkathunyakul, Napat; Corrêa, Ivan R; Bosco, Domenico; Johnson, Paul R; Piemonti, Lorenzo; Marchetti, Piero; Shapiro, A M James; Cochran, Blake J; Hanyaloglu, Aylin C; Inoue, Asuka; Tan, Tricia; Rutter, Guy A; Tomas, Alejandra; Bloom, Stephen R

2018-04-23

Glucagon-like peptide-1 receptor (GLP-1R) activation promotes insulin secretion from pancreatic beta cells, causes weight loss, and is an important pharmacological target in type 2 diabetes (T2D). Like other G protein-coupled receptors, the GLP-1R undergoes agonist-mediated endocytosis, but the functional and therapeutic consequences of modulating GLP-1R endocytic trafficking have not been clearly defined. Here, we investigate a series of biased GLP-1R agonists with variable propensities for GLP-1R internalization and recycling. Compared to a panel of FDA-approved GLP-1 mimetics, compounds that retain GLP-1R at the plasma membrane produce greater long-term insulin release, which is dependent on a reduction in β-arrestin recruitment and faster agonist dissociation rates. Such molecules elicit glycemic benefits in mice without concomitant increases in signs of nausea, a common side effect of GLP-1 therapies. Our study identifies a set of agents with specific GLP-1R trafficking profiles and the potential for greater efficacy and tolerability as T2D treatments.

Discovery of functional monoclonal antibodies targeting G-protein-coupled receptors and ion channels.

PubMed

Wilkinson, Trevor C I

2016-06-15

The development of recombinant antibody therapeutics is a significant area of growth in the pharmaceutical industry with almost 50 approved monoclonal antibodies on the market in the US and Europe. Despite this growth, however, certain classes of important molecular targets have remained intractable to therapeutic antibodies due to complexity of the target molecules. These complex target molecules include G-protein-coupled receptors and ion channels which represent a large potential target class for therapeutic intervention with monoclonal antibodies. Although these targets have typically been addressed by small molecule approaches, the exquisite specificity of antibodies provides a significant opportunity to provide selective modulation of these target proteins. Given this opportunity, substantial effort has been applied to address the technical challenges of targeting these complex membrane proteins with monoclonal antibodies. In this review recent progress made in the strategies for discovery of functional monoclonal antibodies for these challenging membrane protein targets is addressed. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Charomers-Interleukin-6 Receptor Specific Aptamers for Cellular Internalization and Targeted Drug Delivery.

PubMed

Hahn, Ulrich

2017-12-06

Interleukin-6 (IL-6) is a key player in inflammation and the main factor for the induction of acute phase protein biosynthesis. Further to its central role in many aspects of the immune system, IL-6 regulates a variety of homeostatic processes. To interfere with IL-6 dependent diseases, such as various autoimmune diseases or certain cancers like multiple myeloma or hepatocellular carcinoma associated with chronic inflammation, it might be a sensible strategy to target human IL-6 receptor (hIL-6R) presenting cells with aptamers. We therefore have selected and characterized different DNA and RNA aptamers specifically binding IL-6R. These IL-6R aptamers, however, do not interfere with the IL-6 signaling pathway but are internalized with the receptor and thus can serve as vehicles for the delivery of different cargo molecules like therapeutics. We succeeded in the construction of a chlorin e6 derivatized aptamer to be delivered for targeted photodynamic therapy (PDT). Furthermore, we were able to synthesize an aptamer intrinsically comprising the cytostatic 5-Fluoro-2'-deoxy-uridine for targeted chemotherapy. The α6β4 integrin specific DNA aptamer IDA, also selected in our laboratory is internalized, too. All these aptamers can serve as vehicles for targeted drug delivery into cells. We call them charomers-in memory of Charon, the ferryman in Greek mythology, who ferried the deceased into the underworld.

Bombesin related peptides/receptors and their promising therapeutic roles in cancer imaging, targeting and treatment

PubMed Central

Moreno, Paola; Ramos-Álvarez, Irene; Moody, Terry W.; Jensen, Robert T.

2016-01-01

Introduction Despite remarkable advances in tumor treatment, many patients still die from common tumors (breast, prostate, lung, CNS, colon, and pancreas), and thus, new approaches are needed. Many of these tumors synthesize bombesin (Bn)-related peptides and over-express their receptors (BnRs), hence functioning as autocrine-growth-factors. Recent studies support the conclusion that Bn-peptides/BnRs are well-positioned for numerous novel antitumor treatments, including interrupting autocrine-growth via the use of over-expressed receptors for imaging and targeting cytotoxic-compounds, either by direct-coupling or combined with nanoparticle-technology. Areas covered The unique ability of common neoplasms to synthesize, secrete, and show a growth/proliferative/differentiating response due to BnR over-expression, is reviewed, both in general and with regard to the most frequently investigated neoplasms (breast, prostate, lung, and CNS). Particular attention is paid to advances in the recent years. Also considered are the possible therapeutic approaches to the growth/differentiation effect of Bn-peptides, as well as the therapeutic implication of the frequent BnR over-expression for tumor-imaging and/or targeted-delivery. Expert opinion Given that Bn-related-peptides/BnRs are so frequently ectopically-expressed by common tumors, which are often malignant and become refractory to conventional treatments, therapeutic interventions using novel approaches to Bn-peptides and receptors are being explored. Of particular interest is the potential of reproducing BnRs in common tumors, such as the recent success of utilizing overexpression of somatostatin-receptors by neuroendocrine-tumors to provide the most sensitive imaging methods and targeted delivery of cytotoxic-compounds. PMID:26981612

The neural androgen receptor: a therapeutic target for myelin repair in chronic demyelination

PubMed Central

Hussain, Rashad; Ghoumari, Abdel M.; Bielecki, Bartosz; Steibel, Jérôme; Boehm, Nelly; Liere, Philippe; Macklin, Wendy B.; Kumar, Narender; Habert, René; Mhaouty-Kodja, Sakina; Tronche, François; Sitruk-Ware, Regine

2013-01-01

Myelin regeneration is a major therapeutic goal in demyelinating diseases, and the failure to remyelinate rapidly has profound consequences for the health of axons and for brain function. However, there is no efficient treatment for stimulating myelin repair, and current therapies are limited to anti-inflammatory agents. Males are less likely to develop multiple sclerosis than females, but often have a more severe disease course and reach disability milestones at an earlier age than females, and these observations have spurred interest in the potential protective effects of androgens. Here, we demonstrate that testosterone treatment efficiently stimulates the formation of new myelin and reverses myelin damage in chronic demyelinated brain lesions, resulting from the long-term administration of cuprizone, which is toxic for oligodendrocytes. In addition to the strong effect of testosterone on myelin repair, the number of activated astrocytes and microglial cells returned to low control levels, indicating a reduction of neuroinflammatory responses. We also identify the neural androgen receptor as a novel therapeutic target for myelin recovery. After the acute demyelination of cerebellar slices in organotypic culture, the remyelinating actions of testosterone could be mimicked by 5α-dihydrotestosterone, a metabolite that is not converted to oestrogens, and blocked by the androgen receptor antagonist flutamide. Testosterone treatment also failed to promote remyelination after chronic cuprizone-induced demyelination in mice with a non-functional androgen receptor. Importantly, testosterone did not stimulate the formation of new myelin sheaths after specific knockout of the androgen receptor in neurons and macroglial cells. Thus, the neural brain androgen receptor is required for the remyelination effect of testosterone, whereas the presence of the receptor in microglia and in peripheral tissues is not sufficient to enhance remyelination. The potent synthetic

Is androgen receptor targeting an emerging treatment strategy for triple negative breast cancer?

PubMed

Anestis, Aristomenis; Karamouzis, Michalis V; Dalagiorgou, Georgia; Papavassiliou, Athanasios G

2015-06-01

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype. The absence of expression and/or amplification of estrogen and progesterone receptor as well as ERBB-2 prevent the use of currently available endocrine options and/or ERBB-2-directed drugs and indicates chemotherapy as the main current therapy. TNBC represents approximately 15% of breast cancer cases with high index of heterogeneity. Here, we review the role of androgen receptor in breast carcinogenesis and its association with alterations in the expression pattern and functional roles of regulatory molecules and signal transduction pathways in TNBC. Additionally, based on the so far preclinical and clinical published data, we evaluate the perspectives for using and/or developing androgen receptor targeting strategies for specific TNBC subtypes. Copyright © 2015 Elsevier Ltd. All rights reserved.

MicroRNA-29c regulates apoptosis sensitivity via modulation of the cell-surface death receptor, Fas, in lung fibroblasts.

PubMed

Matsushima, Shingo; Ishiyama, Junichi

2016-12-01

MicroRNAs play an important role in the development and progression of various diseases, such as idiopathic pulmonary fibrosis (IPF). Although the accumulation of aberrant fibroblasts resistant to apoptosis is a hallmark in IPF lungs, the mechanism regulating apoptosis susceptibility is not fully understood. Here, we investigated the role of miR-29, which is the most downregulated microRNA in IPF lungs and is also known as a regulator of extracellular matrix (ECM), in the mechanism of apoptosis resistance. We found that functional inhibition of miR-29c caused resistance to Fas-mediated apoptosis in lung fibroblasts. Furthermore, experiments using miR-29c inhibitor and miR-29c mimic revealed that miR-29c regulated expression of the death receptor, Fas, and formation of death-inducing signaling complex leading to extrinsic apoptosis. The representative profibrotic transforming growth factor (TGF)-β downregulated the expression of miR-29c as well as Fas receptor and conferred resistance to apoptosis. We also found that introduction of miR-29c mimic abrogated these TGF-β-induced phenotypes of Fas repression and apoptosis resistance. The results presented here suggest that downregulation of miR-29 observed in IPF lungs may be associated with the apoptosis-resistant phenotype of IPF lung fibroblasts via downregulation of Fas receptor. Therefore, restoration of miR-29 expression in IPF lungs could not only inhibit the accumulation of ECM but also normalize the sensitivity to apoptosis in lung fibroblasts, which may be an effective strategy for treatment of IPF. Copyright © 2016 the American Physiological Society.

Free fatty acids-sensing G protein-coupled receptors in drug targeting and therapeutics.

PubMed

Yonezawa, Tomo; Kurata, Riho; Yoshida, Kaori; Murayama, Masanori A; Cui, Xiaofeng; Hasegawa, Akihiko

2013-01-01

G protein-coupled receptor (GPCR) (also known as seven-transmembrane domain receptor) superfamily represents the largest protein family in the human genome. These receptors respond to various physiological ligands such as photons, odors, pheromones, hormones, ions, and small molecules including amines, amino acids to large peptides and steroids. Thus, GPCRs are involved in many diseases and the target of around half of all conventional drugs. The physiological roles of free fatty acids (FFAs), in particular, long-chain FFAs, are important for the development of many metabolic disease including obesity, diabetes, and atherosclerosis. In the past half decade, deorphanization of several GPCRs has revealed that GPR40, GPR41, GPR43, GPR84 and GPR120 sense concentration of extracellular FFAs with various carbon chain lengths. GPR40 and GPR120 are activated by medium- and long-chain FFAs. GPR84 is activated by medium- chain, but not long-chain, FFAs. GPR41 and GPR43 are activated by short-chain FFAs. GPR40 is highly expressed in pancreatic beta cells and plays a crucial role in FFAs-induced insulin secretion. GPR120 is mainly expressed in enteroendocrine cells and plays an important role for FFAs-induced glucagon-like peptide-1. GPR43 is abundant in leukocytes and adipose tissue, whilst GPR41 is highly expressed in adipose tissue, the pancreas and leukocytes. GPR84 is expressed in leukocytes and monocyte/macrophage. This review aims to shed light on the physiological roles and development of drugs targeting these receptors.

The Endothelin Type A Receptor as a Potential Therapeutic Target in Preeclampsia.

PubMed

Bakrania, Bhavisha; Duncan, Jeremy; Warrington, Junie P; Granger, Joey P

2017-02-28

Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ET A ) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia.

Transferrin receptor-targeted theranostic gold nanoparticles for photosensitizer delivery in brain tumors

PubMed Central

Dixit, Suraj; Novak, Thomas; Miller, Kayla; Zhu, Yun; Kenney, Malcolm E.

2015-01-01

Therapeutic drug delivery across the blood-brain barrier (BBB) is not only inefficient, but also nonspecific to brain stroma. These are major limitations in the effective treatment of brain cancer. Transferrin peptide (Tfpep) targeted gold nanoparticles (Tfpep-Au NPs) loaded with the photodynamic pro-drug, Pc 4, have been designed and compared with untargeted Au NPs for delivery of the photosensitizer to brain cancer cell lines. In vitro studies of human glioma cancer lines (LN229 and U87) overexpressing the transferrin receptor (TfR) show a significant increase in cellular uptake for targeted conjugates as compared to un-targeted particles. Pc 4 delivered from Tfpep-Au NPs clusters within vesicles after targeting with the Tfpep. Pc 4 continues to accumulate over a 4 hour period. Our work suggests that TfR-targeted Au NPs may have important therapeutic implications for delivering brain tumor therapies and/or providing a platform for noninvasive imaging. PMID:25519743

Targeting of nucleotide-binding proteins by HAMLET--a conserved tumor cell death mechanism.

PubMed

Ho, J C S; Nadeem, A; Rydström, A; Puthia, M; Svanborg, C

2016-02-18

HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) kills tumor cells broadly suggesting that conserved survival pathways are perturbed. We now identify nucleotide-binding proteins as HAMLET binding partners, accounting for about 35% of all HAMLET targets in a protein microarray comprising 8000 human proteins. Target kinases were present in all branches of the Kinome tree, including 26 tyrosine kinases, 10 tyrosine kinase-like kinases, 13 homologs of yeast sterile kinases, 4 casein kinase 1 kinases, 15 containing PKA, PKG, PKC family kinases, 15 calcium/calmodulin-dependent protein kinase kinases and 13 kinases from CDK, MAPK, GSK3, CLK families. HAMLET acted as a broad kinase inhibitor in vitro, as defined in a screen of 347 wild-type, 93 mutant, 19 atypical and 17 lipid kinases. Inhibition of phosphorylation was also detected in extracts from HAMLET-treated lung carcinoma cells. In addition, HAMLET recognized 24 Ras family proteins and bound to Ras, RasL11B and Rap1B on the cytoplasmic face of the plasma membrane. Direct cellular interactions between HAMLET and activated Ras family members including Braf were confirmed by co-immunoprecipitation. As a consequence, oncogenic Ras and Braf activity was inhibited and HAMLET and Braf inhibitors synergistically increased tumor cell death in response to HAMLET. Unlike most small molecule kinase inhibitors, HAMLET showed selectivity for tumor cells in vitro and in vivo. The results identify nucleotide-binding proteins as HAMLET targets and suggest that dysregulation of the ATPase/kinase/GTPase machinery contributes to cell death, following the initial, selective recognition of HAMLET by tumor cells. The findings thus provide a molecular basis for the conserved tumoricidal effect of HAMLET, through dysregulation of kinases and oncogenic GTPases, to which tumor cells are addicted.

Targeting receptor-mediated transport for delivery of biologics across the blood-brain barrier.

PubMed

Lajoie, Jason M; Shusta, Eric V

2015-01-01

Biologics are an emerging class of medicines with substantial promise to treat neurological disorders such as Alzheimer's disease, stroke, and multiple sclerosis. However, the blood-brain barrier (BBB) presents a formidable obstacle that appreciably limits brain uptake and hence the therapeutic potential of biologics following intravenous administration. One promising strategy for overcoming the BBB to deliver biologics is the targeting of endogenous receptor-mediated transport (RMT) systems that employ vesicular trafficking to transport ligands across the BBB endothelium. If a biologic is modified with an appropriate targeting ligand, it can gain improved access to the brain via RMT. Various RMT-targeting strategies have been developed over the past 20 years, and this review explores exciting recent advances, emphasizing studies that show brain targeting in vivo.

Nanoparticles for targeted delivery of therapeutics and small interfering RNAs in hepatocellular carcinoma

PubMed Central

Varshosaz, Jaleh; Farzan, Maryam

2015-01-01

Hepatocellular carcinoma (HCC) is the 5th most common malignancy which is responsible for more than half million annual mortalities; also, it is the third leading cause of cancer related death. Unfavorable systemic side-effects of chemotherapeutic agents and susceptibility to the degradation of small interfering RNAs (siRNAs), which can knock down a specific gene involved in the disease, have hampered their clinical application. So, it could be beneficial to develop an efficient carrier for the stabilization and specific delivery of drugs and siRNA to cells. Targeted nanoparticles have gained considerable attention as an efficient drug and gene delivery system, which is due to their capability in achieving the highest accumulation of cytotoxic agents in tumor tissue, modifiable drug pharmacokinetic- and bio-distribution, improved effectiveness of treatment, and limited side-effects. Recent studies have shed more light on the advantages of novel drug loaded carrier systems vs free drugs. Most of the animal studies have reported improvement in treatment efficacy and survival rate using novel carrier systems. Targeted delivery may be achieved passively or actively. In passive targeting, no ligand as homing device is used, while targeting is achieved by incorporating the therapeutic agent into a macromolecule or nanoparticle that passively reaches the target organ. However, in active targeting, the therapeutic agent or carrier system is conjugated to a tissue or cell-specific receptor which is over-expressed in a special malignancy using a ligand called a homing device. This review covers a broad spectrum of targeted nanoparticles as therapeutic and non-viral siRNA delivery systems, which are developed for enhanced cellular uptake and targeted gene silencing in vitro and in vivo and their characteristics and opportunities for the clinical applications of drugs and therapeutic siRNA are discussed in this article. Asialoglycoprotein receptors, low-density lipoprotein

Targeting striatal metabotropic glutamate receptor type 5 in Parkinson's disease: bridging molecular studies and clinical trials.

PubMed

Vallano, A; Fernandez-Duenas, V; Garcia-Negredo, G; Quijada, M A; Simon, C P; Cuffí, M L; Carbonell, L; Sanchez, S; Arnau, J M; Ciruela, F

2013-12-01

Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors expressed primarily on neurons and glial cells modulating the effects of glutamatergic neurotransmission. The pharmacological manipulation of these receptors has been postulated to be valuable in the management of some neurological disorders. Accordingly, the targeting of mGlu5 receptors as a therapeutic approach for Parkinson's disease (PD) has been proposed, especially to manage the adverse symptoms associated to chronic treatment with classical PD drugs. Thus, the specific pharmacological blocking of mGlu5 receptors constitutes one of the most attractive non-dopaminergic-based strategies for PD management in general and for the L-DOPA-induced dyskinesia (LID) in particular. Overall, we provide here an update of the current state of the art of these mGlu5 receptor-based approaches that are under clinical study as agents devoted to alleviate PD symptoms.

Retinoid receptors, transporters, and metabolizers as therapeutic targets in late onset Alzheimer disease.

PubMed

Goodman, Ann B

2006-12-01

Vitamin A (retinoid) is required in the adult brain to enable cognition, learning, and memory. While brain levels of retinoid diminish over the course of normal ageing, retinoid deficit is greater in late onset Alzheimer disease (LOAD) brains than in normal-aged controls. This paper reviews recent evidence supporting these statements and further suggests that genes necessary for the synthesis, transport and function of retinoid to and within the ageing brain are appropriate targets for treatment of LOAD. These genes tend to be clustered with genes that have been proposed as candidates in LOAD, are found at chromosomal regions linked to LOAD, and suggest the possibility of an overall coordinated regulation. This phenomenon is termed Chromeron and is analogous to the operon mechanism observed in prokaryotes. Suggested treatment targets are the retinoic-acid inactivating enzymes (CYP26)s, the retinol binding and transport proteins, retinol-binding protein (RBP)4 and transthyretin (TTR), and the retinoid receptors. TTR as a LOAD target is the subject of active investigation. The retinoid receptors and the retinoid-inactivating enzymes have previously been proposed as targets. This is the first report to suggest that RBP4 is an amenable treatment target in LOAD. RBP4 is elevated in type-2 diabetes and obesity, conditions associated with increased risk for LOAD. Fenretinide, a novel synthetic retinoic acid (RA) analog lowers RBP4 in glucose intolerant obese mice. The feasibility of using fenretinide either as an adjunct to present LOAD therapies, or on its own as an early prevention strategy should be determined. (c) 2006 Wiley-Liss, Inc.

Metabotropic glutamate receptors as therapeutic targets in Parkinson's disease: An update from the last 5 years of research.

PubMed

Litim, Nadhir; Morissette, Marc; Di Paolo, Thérèse

2017-03-15

Disturbance of glutamate neurotransmission in Parkinson's disease (PD) and l-DOPA induced dyskinesia (LID) is well documented. This review focuses on advances during the past five years on pharmacological modulation of metabotropic glutamate (mGlu) receptors in relation to anti-parkinsonian activity, LID attenuation, and neuroprotection. Drug design and characterization have led to the development of orthosteric agonists binding the same site as glutamate and Positive and Negative Allosteric modulators (PAMs and NAMs) binding sites different from the orthosteric site and offering subtype selectivity. Inhibition of group I (mGlu1 and mGlu5) receptors with NAMs and activation of group II (mGlu2 and 3 receptors) and group III (mGlu 4, 7 and 8 receptors) with PAMs and orthosteric agonists have shown their potential to inhibit glutamate release and attenuate excitotoxicity. Earlier and recent studies have led to the development of mGlu5 receptors NAMs to reduce LID and for neuroprotection, mGlu3 receptor agonists for neuroprotection while mGlu4 receptor PAMs and agonists for antiparkinsonian effects and neuroprotection. Furthermore, homo- and heterodimers of mGlu receptors are documented and highlight the complexity of the functioning of these receptors. Research on partial allosteric modulators and biased mGlu receptor allosteric modulators offer new glutamatergic drugs with better therapeutic effects and less off target adverse activity. Thus these various mGlu receptor targets will enable the development of novel drugs with improved clinical effects for normalization of glutamate transmission, treat PD and LID relief. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of ligand-targeted nanoparticles for enhanced cancer targeting

NASA Astrophysics Data System (ADS)

Stefanick, Jared F.

Ligand-targeted nanoparticles are increasingly used as drug delivery vehicles for cancer therapy, yet have not consistently produced successful clinical outcomes. Although these inconsistencies may arise from differences in disease models and target receptors, nanoparticle design parameters can significantly influence therapeutic efficacy. By employing a multifaceted synthetic strategy to prepare peptide-targeted nanoparticles with high purity, reproducibility, and precisely controlled stoichiometry of functionalities, this work evaluates the roles of polyethylene glycol (PEG) coating, ethylene glycol (EG) peptide-linker length, peptide hydrophilicity, peptide density, and nanoparticle size on tumor targeting in a systematic manner. These parameters were analyzed in multiple disease models by targeting human epidermal growth factor receptor 2 (HER2) in breast cancer and very late antigen-4 (VLA-4) in multiple myeloma to demonstrate the widespread applicability of this approach. By increasing the hydrophilicity of the targeting peptide sequence and simultaneously optimizing the EG peptide-linker length, the in vitro cellular uptake of targeted liposomes was significantly enhanced. Specifically, including a short oligolysine chain adjacent to the targeting peptide sequence effectively increased cellular uptake ~80-fold using an EG6 peptide-linker compared to ~10-fold using an EG45 linker. In vivo, targeted liposomes prepared in a traditional manner lacking the oligolysine chain demonstrated similar biodistribution and tumor uptake to non-targeted liposomes. However, by including the oligolysine chain, targeted liposomes using an EG45 linker significantly improved tumor uptake ~8-fold over non-targeted liposomes, while the use of an EG6 linker decreased tumor accumulation and uptake, owing to differences in cellular uptake kinetics, clearance mechanisms, and binding site barrier effects. To further improve tumor targeting and enhance the selectivity of targeted

Post-Transcriptional Control of Angiotensin II Type 1 Receptor Regulates Osteosarcoma Cell Death.

PubMed

Zhao, Yue; Xu, Kaicheng; Liu, Peng

2018-01-01

MicroRNAs (miRNAs) play an essential role in the tumorigenesis of osteosarcoma (OS). However, the effects of miR-1248 on chemo-resistant potential of OS have not been studied. Here, we addressed this question. The levels of miR-1248 and apoptotic protein angiotensin II type 1 receptor (AGTR1) in OS specimens were examined by RT-qPCR and Western blotting, respectively. The relationship between miR-1248 and AGTR1 was determined by analysis of Spearman's Rank Correlation Coefficients. The patient survival was determined with Kaplan-Meier curves. Bioinformatics analyses were done to predict microRNAs (miRNAs) that target AGTR1. The functional binding of miRNAs to AGTR1 mRNA was examined by a dual luciferase reporter assay. Cell viability was determined by an CCK-8 assay. Apoptosis was determined by a fluorescence-based apoptosis assay. The levels of miR-1248 were significantly elevated while the levels of AGTR1 were significantly decreased in OS specimens than in paired adjacent normal tissue. The levels of miR-1248 were negatively correlated to the levels of AGTR1. Moreover, the patients with high miR-1248 levels had poorer survival than those with low MiR-1248 levels, and the patients with low AGTR1 levels had poorer survival than those with high AGTR1 levels. MiR-1248 inhibited protein translation of AGTR1, through binding to the 3'-UTR of the AGTR1 mRNA. The AGTR1-mediated cell apoptosis was suppressed by overexpressing miR-1248, and was augmented by depleting miR-1248. Increased miR-1248 expression in OS may inhibit AGTR1-mediated cancer cell death in chemotherapy. The outcome of chemotherapy may be improved by the suppression of miR-1248 in OS cells. © 2018 The Author(s). Published by S. Karger AG, Basel.

A bi-functional antibody-receptor domain fusion protein simultaneously targeting IGF-IR and VEGF for degradation

PubMed Central

Shen, Yang; Zeng, Lin; Novosyadlyy, Ruslan; Forest, Amelie; Zhu, Aiping; Korytko, Andrew; Zhang, Haifan; Eastman, Scott W; Topper, Michael; Hindi, Sagit; Covino, Nicole; Persaud, Kris; Kang, Yun; Burtrum, Douglas; Surguladze, David; Prewett, Marie; Chintharlapalli, Sudhakar; Wroblewski, Victor J; Shen, Juqun; Balderes, Paul; Zhu, Zhenping; Snavely, Marshall; Ludwig, Dale L

2015-01-01

Bi-specific antibodies (BsAbs), which can simultaneously block 2 tumor targets, have emerged as promising therapeutic alternatives to combinations of individual monoclonal antibodies. Here, we describe the engineering and development of a novel, human bi-functional antibody-receptor domain fusion molecule with ligand capture (bi-AbCap) through the fusion of the domain 2 of human vascular endothelial growth factor receptor 1 (VEGFR1) to an antibody directed against insulin-like growth factor – type I receptor (IGF-IR). The bi-AbCap possesses excellent stability and developability, and is the result of minimal engineering. Beyond potent neutralizing activities against IGF-IR and VEGF, the bi-AbCap is capable of cross-linking VEGF to IGF-IR, leading to co-internalization and degradation of both targets by tumor cells. In multiple mouse xenograft tumor models, the bi-AbCap improves anti-tumor activity over individual monotherapies. More importantly, it exhibits superior inhibition of tumor growth, compared with the combination of anti-IGF-IR and anti-VEGF therapies, via powerful blockade of both direct tumor cell growth and tumor angiogenesis. The unique “capture-for-degradation” mechanism of the bi-AbCap is informative for the design of next-generation bi-functional anti-cancer therapies directed against independent signaling pathways. The bi-AbCap design represents an alternative approach to the creation of dual-targeting antibody fusion molecules by taking advantage of natural receptor-ligand interactions. PMID:26073904