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Kinnosuke Yahiro, Sayaka Nagasawa, Kimitoshi Ichimura, Hiroki Takeuchi, Kohei Ogura, Hiroyasu Tsutsuki, Takeshi Shimizu, Sunao Iyoda, Makoto Ohnishi, Hirotaro Iwase, Joel Moss, Masatoshi Noda
Shiga toxigenic Escherichia coli (STEC) are responsible for a worldwide foodborne disease, which is characterized by severe bloody diarrhea and hemolytic uremic syndrome (HUS). Subtilase cytotoxin (SubAB) is a novel AB5 toxin, which is produced by Locus for Enterocyte Effacement (LEE)-negative STEC. Cleavage of the BiP protein by SubAB induces endoplasmic reticulum (ER) stress, followed by induction of cytotoxicity in vitro or lethal severe hemorrhagic inflammation in mice. Here we found that steroids and diacylglycerol (DAG) analogues (e...
December 2018: Cell Death Discovery
Xiguang Zhao, Noemi Kedei, Aleksandra M Michalowski, Nancy E Lewin, Gary E Keck, Peter M Blumberg
Important strides are being made in understanding the structural features of bryostatin 1, a candidate therapeutic agent for cancer and dementia, conferring its potency for protein kinase C and the unique spectrum of biological responses which it induces. A critical pharmacophoric element in bryostatin 1 is a secondary hydroxyl, whereas a primary hydroxyl group plays the analogous role in binding of the phorbol esters to protein kinase C. Here, we describe the synthesis of a bryostatin homolog where the hydroxyl group is primary, as in the phorbol esters, and show that its biological activity is almost indistinguishable from that of the corresponding compound with the secondary hydroxyl group...
March 8, 2018: Chembiochem: a European Journal of Chemical Biology
Michael D Kornberg, Matthew D Smith, Hasti Atashi Shirazi, Peter A Calabresi, Solomon H Snyder, Paul M Kim
Multiple sclerosis (MS) is an inflammatory disorder targeting the central nervous system (CNS). The relapsing-remitting phase of MS is largely driven by peripheral activation of autoreactive T-helper (Th) 1 and Th17 lymphocytes. In contrast, compartmentalized inflammation within the CNS, including diffuse activation of innate myeloid cells, characterizes the progressive phase of MS, the most debilitating phase that currently lacks satisfactory treatments. Recently, bryostatin-1 (bryo-1), a naturally occurring, CNS-permeable compound with a favorable safety profile in humans, has been shown to act on antigen-presenting cells to promote differentiation of lymphocytes into Th2 cells, an action that might benefit Th1-driven inflammatory conditions such as MS...
February 27, 2018: Proceedings of the National Academy of Sciences of the United States of America
Thomas J Cummins, Noemi Kedei, Agnes Czikora, Nancy E Lewin, Sharon Kirk, Mark E Petersen, Kevin M McGowan, Jin-Qiu Chen, Xiaoling Luo, Randall C Johnson, Sarangan Ravichandran, Peter M Blumberg, Gary E Keck
To investigate the cellular distribution of tumor-promoting vs nontumor-promoting bryostatin analogues, we synthesized fluorescently labeled variants of two bryostatin derivatives that have previously shown either phorbol ester-like or bryostatin-like biological activity on U937 cells. These new fluorescent analogues both displayed high affinity for PKC binding and retained the basic properties of the parent, unlabeled compounds in U937 assays. The fluorescent compounds showed similar patterns of intracellular distribution in cells, however, arguing against an existing hypothesis that varying patterns of intracellular distribution contributed to the difference in biological activity...
February 9, 2018: Chembiochem: a European Journal of Chemical Biology
Hao Yang, Daryl Staveness, Steven M Ryckbosch, Alison D Axtman, Brian A Loy, Alexander B Barnes, Vijay S Pande, Jacob Schaefer, Paul A Wender, Lynette Cegelski
Bryostatin 1 (henceforth bryostatin) is in clinical trials for the treatment of Alzheimer's disease and for HIV/AIDS eradication. It is also a preclinical lead for cancer immunotherapy and other therapeutic indications. Yet nothing is known about the conformation of bryostatin bound to its protein kinase C (PKC) target in a membrane microenvironment. As a result, efforts to design more efficacious, better tolerated, or more synthetically accessible ligands have been limited to structures that do not include PKC or membrane effects known to influence PKC-ligand binding...
January 24, 2018: ACS Central Science
Elsayed I Salim, Samar F Harras, Aisha G Abdalla, Mohmmed H Mona
Accumulating evidence suggest that some infectious agents may interfere in the natural progression of neoplasia. This study examined the association between chronic infection with adult Syphacia muris parasites and 1,2-dimethylhydrazine (DMH)-induced colorectal carcinogenesis in rats. In addition, the conceivable therapeutic effect of Bryostatin-1, a potent extract of the marine Bryozoan, Bugulane ritina, was investigated against this combined effect.DMH administration has induced aberrant crypt foci (ACF), surrogate biomarkers for colorectal carcinogenesis, while the S...
March 26, 2018: Acta Parasitologica
Thomas D Zaikos, Mark M Painter, Nadia T Sebastian, Valeri H Terry, Kathleen L Collins
Combinations of drugs that affect distinct mechanisms of HIV latency aim to induce robust latency reversal leading to cytopathicity and elimination of the persistent HIV reservoir. Thus far, attempts have focused on combinations of PKC agonists and pan-histone deacetylase inhibitors (HDIs) despite the knowledge that HIV gene expression is regulated by class 1 histone deacetylases. We hypothesized that class 1-selective HDIs would promote more robust HIV latency reversal in combination with a PKC agonist than pan-HDIs because they preserve the activity of pro-viral factors regulated by non-class 1 histone deacetylases...
January 3, 2018: Journal of Virology
Alizé Proust, Corinne Barat, Mathieu Leboeuf, Jean Drouin, Michel J Tremblay
BACKGROUND: Despite effectiveness of the combined antiretroviral therapy, HIV-1 persists in long-lived latently infected cells. Consequently, new therapeutic approaches aimed at eliminating this latent reservoir are currently being developed. A "shock and kill" strategy using latency-reversing agents (LRA) to reactivate HIV-1 has been proposed. However, the impact of LRA on the central nervous system (CNS) remains elusive. METHODS: We used human fetal astrocytes and investigated the effects of several LRA on their functional and secretory activities...
December 11, 2017: Journal of Neuroinflammation
Yuebao Zhang, Qianyou Guo, Xianwei Sun, Ji Lu, Yanjun Cao, Qiang Pu, Zhiwen Chu, Lu Gao, Zhenlei Song
Convergent total synthesis of bryostatin 8 has been accomplished by an organosilane-based strategy. The C ring is constructed stereoselectively through a geminal bis(silane)-based [1,5]-Brook rearrangement, and the B ring through geminal bis(silane)-based Prins cyclization, thus efficiently joining the northern and southern parts of the molecule.
January 22, 2018: Angewandte Chemie
Ning Zeng, Yi Xu, Yiping Wu, Tang Hongbo, Min Wu
The present study was designed to investigate the tumor inhibitory potential of bryostatin 1 in a 12‑O‑tetradecanoylphorbol‑13‑acetate (TPA)‑induced mouse model of skin cancer. The radical inhibition potential of various doses of bryostatin 1 was investigated against 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) bleach in vitro. The DPPH radical potential was observed compared with treatment with 5, 10, 15, 20, 25 and 30 µM doses of bryostatin 1. In vivo, bryostatin 1 prevented the TPA‑mediated increase in the level of H2O2 and myeloperoxidase in mouse epidermal tissue...
January 2018: Molecular Medicine Reports
Anthony P Green, Simon Hardy, Alan T L Lee, Eric J Thomas
The first total synthesis of a derivative of a 20-deoxybryostatin, namely 7-des-O-pivaloyl-7-O-benzylbryostatin 10 is described. Preliminary studies demonstrated that the modified Julia reactions of 2-benzothiazolylsulfones corresponding to the C17-C27 fragment with aldehydes corresponding to the C1-C16 fragment, provided an efficient and stereoselective assembly of advanced intermediates with the (E)-16,17-double-bond. The synthesis of the C1-C16 fragment was then modified so that the C1 acid was present as its allyl ester before the Julia coupling...
November 15, 2017: Organic & Biomolecular Chemistry
Anthony P Green, Simon Hardy, Eric J Thomas
The modified Julia reaction and acyl carbanion chemistry, especially reactions of 2-lithiated dithianes, have been investigated for the synthesis of intermediates that are the synthetic equivalents of the C11-C27 fragments of bryostatins. The modified Julia reaction using 2-benzothiazolylsulfones was found to be more useful for the formation of the C16-C17 double-bond than the classical Julia reaction using phenylsulfones, and bulky sulfones gave very good (E)-stereoselectivity. The alkylation of a dithiane monoxide that corresponded to a C19-acyl carbanion using (E)-1-bromobut-2-ene was efficient but the use of a more complex allylic bromide corresponding to the C20-C27 fragment of the bryostatins was unsuccessful, possibly due to competing elimination reactions...
November 15, 2017: Organic & Biomolecular Chemistry
(no author information available yet)
Scientists have come up with an efficient, scalable way to chemically synthesize bryostatin 1, a marine-derived natural PKC modulator that has been in scarce supply, impeding a thorough evaluation of its therapeutic potential.
December 2017: Cancer Discovery
Paul A Wender, Clayton T Hardman, Stephen Ho, Matthew S Jeffreys, Jana K Maclaren, Ryan V Quiroz, Steven M Ryckbosch, Akira J Shimizu, Jack L Sloane, Matthew C Stevens
Bryostatin 1 is an exceedingly scarce marine-derived natural product that is in clinical development directed at HIV/AIDS eradication, cancer immunotherapy, and the treatment of Alzheimer's disease. Despite this unique portfolio of indications, its availability has been limited and variable, thus impeding research and clinical studies. Here, we report a total synthesis of bryostatin 1 that proceeds in 29 total steps (19 in the longest linear sequence, >80% average yield per step), collectively produces grams of material, and can be scaled to meet clinical needs (~20 grams per year)...
October 13, 2017: Science
Matthew D Marsden, Brian A Loy, Xiaomeng Wu, Christina M Ramirez, Adam J Schrier, Danielle Murray, Akira Shimizu, Steven M Ryckbosch, Katherine E Near, Tae-Wook Chun, Paul A Wender, Jerome A Zack
The ability of HIV to establish a long-lived latent infection within resting CD4+ T cells leads to persistence and episodic resupply of the virus in patients treated with antiretroviral therapy (ART), thereby preventing eradication of the disease. Protein kinase C (PKC) modulators such as bryostatin 1 can activate these latently infected cells, potentially leading to their elimination by virus-mediated cytopathic effects, the host's immune response and/or therapeutic strategies targeting cells actively expressing virus...
September 2017: PLoS Pathogens
Ji Lu, Yuebao Zhang, WenYu Yang, Qianyou Guo, Lu Gao, Zhenlei Song
An interesting approach to transform the B ring of bryostatins to the C ring has been developed. The key tactics of the approach feature an intramolecular Csp(3)-H bond amination to form spirocyclic hemiaminal, which undergoes ring opening to afford the C ring found in bryostatin 17. The subsequent epoxidation/oxidation sequence results in Z to E isomerization of the exo-cyclic enoate, delivering the common precursor, which could be transformed into the C ring found in bryostatins 1, 2, 4-9, 12, 14, and 15.
October 6, 2017: Organic Letters
Leena P Bharath, Jae Min Cho, Seul-Ki Park, Ting Ruan, Youyou Li, Robert Mueller, Tyler Bean, Van Reese, Russel S Richardson, Jinjin Cai, Ashot Sargsyan, Karla Pires, Pon Velayutham Anandh Babu, Sihem Boudina, Timothy E Graham, J David Symons
OBJECTIVE: Impaired endothelial cell (EC) autophagy compromises shear stress-induced nitric oxide (NO) generation. We determined the responsible mechanism. APPROACH AND RESULTS: On autophagy compromise in bovine aortic ECs exposed to shear stress, a decrease in glucose uptake and EC glycolysis attenuated ATP production. We hypothesized that decreased glycolysis-dependent purinergic signaling via P2Y1 (P2Y purinoceptor 1) receptors, secondary to impaired autophagy in ECs, prevents shear-induced phosphorylation of eNOS (endothelial nitric oxide synthase) at its positive regulatory site S1117 (p-eNOS(S1177)) and NO generation...
September 2017: Arteriosclerosis, Thrombosis, and Vascular Biology
Jahahreeh Finley
Although promising treatments are currently in development to slow disease progression and increase patient survival, cancer remains the second leading cause of death in the United States. Cancer treatment modalities commonly include chemoradiation and therapies that target components of aberrantly activated signaling pathways. However, treatment resistance is a common occurrence and recent evidence indicates that the existence of cancer stem cells (CSCs) may underlie the limited efficacy and inability of current treatments to effectuate a cure...
July 2017: Medical Hypotheses
Huachao Huang, Shuai Liu, Maxime Jean, Sydney Simpson, He Huang, Mark Merkley, Tsuyoshi Hayashi, Weili Kong, Irene Rodríguez-Sánchez, Xiaofeng Zhang, Hailemichael O Yosief, Hongyu Miao, Jianwen Que, James J Kobie, James Bradner, Netty G Santoso, Wei Zhang, Jian Zhu
While combinatory antiretroviral therapy (cART) can effectively reduce HIV-1 viremia, it cannot eliminate HIV-1 infection. In the presence of cART, viral reservoirs remain latent, impeding the cure of HIV-1/AIDS. Recently, latency-reversing agents (LRAs) have been developed with the intent of purging latent HIV-1, providing an intriguing strategy for the eradication of the residual viral reservoirs. Our earlier studies show that the first-generation, methyl-triazolo bromodomain, and extra-terminal domain inhibitor (BETi), JQ1, facilitates the reversal of HIV-1 latency...
2017: Frontiers in Microbiology
Yeji Lee, Chanvorleak Phat, Soon-Cheol Hong
Many cyclic peptides and analogues derived from marine sources are known to possess biological properties, including anticancer, antitumor, antibacterial, antifungal, antiparasitic, anti-inflammation, anti-proliferative, anti-hypertensive, cytotoxic, and antibiotic properties. These compounds demonstrate different activities and modes of action according to their structure such as cyclic oligopeptide, cyclic lipopeptide, cyclic glycopeptide and cyclic depsipeptide. The recent advances in application of the above-mentioned cyclic peptides were reported in dolastatins, soblidotin, didemnin B, aplidine, salinosporamide A, kahalalide F and bryostatin 1 and they are currently in clinical trials...
September 2017: Peptides
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