1
|
Tian Z, Lu XT, Jiang X, Tian J. Bryostatin-1: a promising compound for neurological disorders. Front Pharmacol 2023; 14:1187411. [PMID: 37351510 PMCID: PMC10282138 DOI: 10.3389/fphar.2023.1187411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/23/2023] [Indexed: 06/24/2023] Open
Abstract
The central nervous system (CNS) is the most complex system in human body, and there is often a lack of effective treatment strategies for the disorders related with CNS. Natural compounds with multiple pharmacological activities may offer better options because they have broad cellular targets and potentially produce synergic and integrative effects. Bryostatin-1 is one of such promising compounds, a macrolide separated from marine invertebrates. Bryostatin-1 has been shown to produce various biological activities through binding with protein kinase C (PKC). In this review, we mainly summarize the pharmacological effects of bryostatin-1 in the treatment of multiple neurological diseases in preclinical studies and clinical trials. Bryostatin-1 is shown to have great therapeutic potential for Alzheimer's disease, multiple sclerosis, fragile X syndrome, stroke, traumatic brain injury, and depression. It exhibits significant rescuing effects on the deficits of spatial learning, cognitive function, memory and other neurological functions caused by diseases, producing good neuroprotective effects. The promising neuropharmacological activities of bryostatin-1 suggest that it is a potential candidate for the treatment of related neurological disorders although there are still some issues needed to be addressed before its application in clinic.
Collapse
Affiliation(s)
- Zhen Tian
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Xin-Tong Lu
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Xun Jiang
- Department of Pediatrics, Tangdu Hospital of Fourth Military Medical University, Xi’an, China
| | - Jiao Tian
- Department of Infection, Children’s Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Child Infection and Immunity, The First Batch of Key Disciplines on Public Health in Chongqing, Chongqing, China
| |
Collapse
|
2
|
Activators and Inhibitors of Protein Kinase C (PKC): Their Applications in Clinical Trials. Pharmaceutics 2021; 13:pharmaceutics13111748. [PMID: 34834162 PMCID: PMC8621927 DOI: 10.3390/pharmaceutics13111748] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 02/05/2023] Open
Abstract
Protein kinase C (PKC), a family of phospholipid-dependent serine/threonine kinase, is classed into three subfamilies based on their structural and activation characteristics: conventional or classic PKC isozymes (cPKCs; α, βI, βII, and γ), novel or non-classic PKC isozymes (nPKCs; δ, ε, η, and θ), and atypical PKC isozymes (aPKCs; ζ, ι, and λ). PKC inhibitors and activators are used to understand PKC-mediated intracellular signaling pathways and for the diagnosis and treatment of various PKC-associated diseases, such as cancers, neurological diseases, cardiovascular diseases, and infections. Many clinical trials of PKC inhibitors in cancers showed no significant clinical benefits, meaning that there is a limitation to design a cancer therapeutic strategy targeting PKC alone. This review will focus on the activators and inhibitors of PKC and their applications in clinical trials.
Collapse
|
3
|
Raghuvanshi R, Bharate SB. Preclinical and Clinical Studies on Bryostatins, A Class of Marine-Derived Protein Kinase C Modulators: A Mini-Review. Curr Top Med Chem 2021; 20:1124-1135. [PMID: 32209043 DOI: 10.2174/1568026620666200325110444] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/11/2020] [Accepted: 02/24/2020] [Indexed: 12/20/2022]
Abstract
Bryostatins are complex macrolactones isolated from marine organisms Bryozoan Bugula neritina. They are potent modulators of protein kinase C isozymes (PKCα: ki = 1.3-188 nM), and are one of the most extensively investigated marine natural products in clinical trials. Although ~21 natural bryostatins have been isolated, however only bryostatin-1 (1) has received much interest among medicinal chemists and clinicians. The structure-activity relationship of bryostatins has been well established, with the identification of key pharmacophoric features important for PKC modulation. The low natural abundance and the long synthetic route have prompted medicinal chemists to come-up with simplified analogs. Bryostatin skeleton comprises three pyran rings connected to each other to form a macrocyclic lactone. The simplest analog 27 contains only one pyran, which is also able to modulate the PKCα activity; however, the cyclic framework appears to be essential for the desired level of potency. Another simplified analog 17 ("picolog") exhibited potent and in-vivo efficacy against lymphoma. Bryostatin-1 (1) has shown an acceptable intravenous pharmacokinetic profile in mice and displayed promising in-vivo efficacy in mice models of various cancers and Alzheimer's disease. Bryostatin-1 was investigated in numerous Phase I/II oncology clinical trials; it has shown minimal effect as a single agent, however, provided encouraging results in combination with other chemotherapy agents. FDA has granted orphan drug status to bryostatin-1 in combination with paclitaxel for esophageal cancer. Bryostatin-1 has also received orphan drug status for fragile X syndrome. Bryostatin-1 was also investigated in clinical studies for Alzheimer's disease and HIV infection. In a nutshell, the natural as well as synthetic bryostatins have generated a strong hope to emerge as treatment for cancer along with many other diseases.
Collapse
Affiliation(s)
- Rinky Raghuvanshi
- Medicinal Chemistry Division, CSIR- Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Sandip B Bharate
- Medicinal Chemistry Division, CSIR- Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad-201002, India
| |
Collapse
|
4
|
Prodrugs of PKC modulators show enhanced HIV latency reversal and an expanded therapeutic window. Proc Natl Acad Sci U S A 2020; 117:10688-10698. [PMID: 32371485 DOI: 10.1073/pnas.1919408117] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIDS is a pandemic disease caused by HIV that affects 37 million people worldwide. Current antiretroviral therapy slows disease progression but does not eliminate latently infected cells, which resupply active virus, thus necessitating lifelong treatment with associated compliance, cost, and chemoexposure issues. Latency-reversing agents (LRAs) activate these cells, allowing for their potential clearance, thus presenting a strategy to eradicate the infection. Protein kinase C (PKC) modulators-including prostratin, ingenol esters, bryostatin, and their analogs-are potent LRAs in various stages of development for several clinical indications. While LRAs are promising, a major challenge associated with their clinical use is sustaining therapeutically meaningful levels of the active agent while minimizing side effects. Here we describe a strategy to address this problem based on LRA prodrugs, designed for controllable release of the active LRA after a single injection. As intended, these prodrugs exhibit comparable or superior in vitro activity relative to the parent compounds. Selected compounds induced higher in vivo expression of CD69, an activation biomarker, and, by releasing free agent over time, significantly improved tolerability when compared to the parent LRAs. More generally, selected prodrugs of PKC modulators avoid the bolus toxicities of the parent drug and exhibit greater efficacy and expanded tolerability, thereby addressing a longstanding objective for many clinical applications.
Collapse
|
5
|
Abstract
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. In the present study, we show that bryo-1 provides marked benefit in mice with experimental autoimmune encephalomyelitis (EAE), an experimental MS animal model. Preventive treatment with bryo-1 abolishes the onset of neurologic deficits in EAE. More strikingly, bryo-1 reverses neurologic deficits after EAE onset, even when treatment is initiated at a late stage of disease when peak adaptive immunity has subsided. Treatment with bryo-1 in vitro promotes an anti-inflammatory phenotype in antigen-presenting dendritic cells, macrophages, and to a lesser extent, lymphocytes. These findings suggest the potential for bryo-1 as a therapeutic agent in MS, particularly given its established clinical safety. Furthermore, the benefit of bryo-1, even in late treatment of EAE, combined with its targeting of innate myeloid cells suggests therapeutic potential in progressive forms of MS.
Collapse
|
6
|
Isakov N. Protein kinase C (PKC) isoforms in cancer, tumor promotion and tumor suppression. Semin Cancer Biol 2017; 48:36-52. [PMID: 28571764 DOI: 10.1016/j.semcancer.2017.04.012] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 04/25/2017] [Indexed: 12/27/2022]
Abstract
The AGC family of serine/threonine kinases (PKA, PKG, PKC) includes more than 60 members that are critical regulators of numerous cellular functions, including cell cycle and differentiation, morphogenesis, and cell survival and death. Mutation and/or dysregulation of AGC kinases can lead to malignant cell transformation and contribute to the pathogenesis of many human diseases. Members of one subgroup of AGC kinases, the protein kinase C (PKC), have been singled out as critical players in carcinogenesis, following their identification as the intracellular receptors of phorbol esters, which exhibit tumor-promoting activities. This observation attracted the attention of researchers worldwide and led to intense investigations on the role of PKC in cell transformation and the potential use of PKC as therapeutic drug targets in cancer diseases. Studies demonstrated that many cancers had altered expression and/or mutation of specific PKC genes. However, the causal relationships between the changes in PKC gene expression and/or mutation and the direct cause of cancer remain elusive. Independent studies in normal cells demonstrated that activation of PKC is essential for the induction of cell activation and proliferation, differentiation, motility, and survival. Based on these observations and the general assumption that PKC isoforms play a positive role in cell transformation and/or cancer progression, many PKC inhibitors have entered clinical trials but the numerous attempts to target PKC in cancer has so far yielded only very limited success. More recent studies demonstrated that PKC function as tumor suppressors, and suggested that future clinical efforts should focus on restoring, rather than inhibiting, PKC activity. The present manuscript provides some historical perspectives on the tumor promoting function of PKC, reviewing some of the observations linking PKC to cancer progression, and discusses the role of PKC in the pathogenesis of cancer diseases and its potential usage as a therapeutic target.
Collapse
Affiliation(s)
- Noah Isakov
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
| |
Collapse
|
7
|
Cancer Research UK Centre for Drug Development: translating 21st-century science into the cancer medicines of tomorrow. Drug Discov Today 2015; 20:995-1003. [PMID: 25794601 DOI: 10.1016/j.drudis.2015.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/19/2015] [Accepted: 03/11/2015] [Indexed: 01/14/2023]
Abstract
The Cancer Research UK Centre (CRUK) for Drug Development (CDD) can trace its origins back to the Cancer Research Campaign Phase I/II Committee (created in 1980) and to date has tested over 120 potential cancer medicines in early-phase clinical trials. Five drugs are now registered, providing benefit to thousands of patients with cancer as part of their routine standard of care. In recent years, the CDD has established several different business and operating models that provide it with access to the pipelines of pharmaceutical and biotechnology companies. This has enabled potential new treatments to be taken into clinical development that might have otherwise languished on companies' shelves and has increased the number of drug combinations being explored in early-phase clinical trials.
Collapse
|
8
|
Mikhail S, Albanese C, Pishvaian MJ. Cyclin-dependent kinase inhibitors and the treatment of gastrointestinal cancers. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:1185-97. [PMID: 25747534 DOI: 10.1016/j.ajpath.2015.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/23/2014] [Accepted: 01/13/2015] [Indexed: 01/14/2023]
Abstract
The cell cycle is a highly conserved and tightly regulated biological system that controls cellular proliferation and differentiation. The cell cycle regulatory proteins, which include the cyclins, the cyclin-dependent kinases (CDKs), and the CDK inhibitors, are critical for the proper temporal and spatial regulation of cellular proliferation. Conversely, alterations in cell cycle regulatory proteins, leading to the loss of normal cell-cycle control, are a hallmark of many cancers, including gastrointestinal cancers. Accordingly, overexpression of CDKs and cyclins and by contrast loss of CDK inhibitors, are all linked to gastrointestinal cancers and are often associated with less favorable prognoses and outcomes. Because of the importance that the cell cycle regulatory proteins play in tumorigenesis, currently there is a broad spectrum of cell-cycle inhibitors under development that, as a group, hold promise as effective cancer treatments. In support of this approach to cancer treatment, the growing availability of molecular diagnostics techniques may help in identifying patients who have driving abnormalities in the cell-cycle machinery and are thus more likely to respond to cell-cycle inhibitors. In this review, we discuss the prevalence of cell-cycle abnormalities in patients with gastrointestinal cancers and provide a preclinical and clinical overview of new agents that target cell-cycle abnormalities with a special emphasis on gastrointestinal cancers.
Collapse
Affiliation(s)
- Sameh Mikhail
- James Cancer Hospital and Solove Research Institute, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio
| | - Christopher Albanese
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia; Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia.
| | - Michael J Pishvaian
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia
| |
Collapse
|
9
|
Indumathy S, Dass CR. Finding chemo: the search for marine-based pharmaceutical drugs active against cancer. ACTA ACUST UNITED AC 2013; 65:1280-301. [PMID: 23927467 DOI: 10.1111/jphp.12097] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/29/2013] [Indexed: 12/26/2022]
Abstract
OBJECTIVES Cancer affects the health of many people globally. The most common treatment that is used for cancer is chemotherapy, which has shown promising results but not without side effects. Some of these side effects jeopardise further treatment, and this eventually leads to advanced stages of malignancy and mortality. As a result, there is a need for better and safer anticancer compounds such as those found naturally. One of the most abundant natural environments to find such compounds is the sea, and this vast resource has been biomined since the 1950s. KEY FINDINGS There are currently three marine anticancer agents marketed (Yondelis, Cytosar-U and Halaven), with several others undergoing clinical trials. This review discusses marine-derived products in clinical use and in clinical trials, and discusses available literature on the growth suppression or pro-apoptotic properties of these compounds, and the molecular mechanisms underpinning these cell biological phenomena. SUMMARY The marine environment may hold promising anticancer compounds within its depths, warranting further research to be performed in this area, albeit with respect for the natural ecosystems that are being explored for drug discover and subsequently used for drug development.
Collapse
Affiliation(s)
- Sivanjah Indumathy
- College of Biomedicine and Health, Victoria University, St Albans, Vic, Australia
| | | |
Collapse
|
10
|
Wang YQ, Miao ZH. Marine-derived angiogenesis inhibitors for cancer therapy. Mar Drugs 2013; 11:903-33. [PMID: 23502698 PMCID: PMC3705379 DOI: 10.3390/md11030903] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 02/25/2013] [Accepted: 03/01/2013] [Indexed: 12/18/2022] Open
Abstract
Angiogenesis inhibitors have been successfully used for cancer therapy in the clinic. Many marine-derived natural products and their analogues have been reported to show antiangiogenic activities. Compared with the drugs in the clinic, these agents display interesting characteristics, including diverse sources, unique chemical structures, special modes of action, and distinct activity and toxicity profiles. This review will first provide an overview of the current marine-derived angiogenesis inhibitors based on their primary targets and/or mechanisms of action. Then, the marine-derived antiangiogenic protein kinase inhibitors will be focused on. And finally, the clinical trials of the marine-derived antiangiogenic agents will be discussed, with special emphasis on their application potentials, problems and possible coping strategies in their future development as anticancer drugs.
Collapse
Affiliation(s)
- Ying-Qing Wang
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China.
| | | |
Collapse
|
11
|
Protein Kinase C: One Pathway towards the Eradication of Latent HIV-1 Reservoirs. Adv Virol 2012; 2012:805347. [PMID: 22500169 PMCID: PMC3303757 DOI: 10.1155/2012/805347] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 12/23/2011] [Indexed: 01/15/2023] Open
Abstract
An effective means to eradicate latent reservoirs in HIV-1-infected individuals remains elusive. Attempts to purge these reservoirs were undertaken over a decade ago without success. The subsequent lapse in further clinical attempts since may have been justified as our knowledge of the mechanisms which underpin the latent state still evolves. Although additional novel molecular antagonists of HIV-1 latency have subsequently been reported, these candidate agents have not been tested in human trials for reservoir ablation. This review provides an overview of the protein kinase C (PKC) pathway which can be modulated by small molecular agents to induce the expression of latent HIV-1 from within infected reservoir cells. Some of these agents have been tested against select cancers with seemingly tolerable side effects. As such, modulation of the PKC pathway may yet be a viable mechanism toward HIV-1 reservoir eradication.
Collapse
|
12
|
Usha L, Sill MW, Darcy KM, Benbrook DM, Hurteau JA, Michelin DP, Mannel RS, Hanjani P, De Geest K, Godwin AK. A Gynecologic Oncology Group phase II trial of the protein kinase C-beta inhibitor, enzastaurin and evaluation of markers with potential predictive and prognostic value in persistent or recurrent epithelial ovarian and primary peritoneal malignancies. Gynecol Oncol 2011; 121:455-61. [PMID: 21414654 PMCID: PMC3100412 DOI: 10.1016/j.ygyno.2011.02.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 01/20/2023]
Abstract
OBJECTIVES Protein kinase C (PKC) activation contributes to proliferation and angiogenesis in epithelial ovarian or primary peritoneal carcinoma (EOC/PPC). A multi-institutional phase II trial was conducted to evaluate the efficacy and safety of PKCβ inhibitor enzastaurin in persistent or recurrent EOC/PPC and to explore potential prognostic and predictive biomarkers. METHODS Eligible women with measurable platinum-sensitive and resistant EOC/PPC were treated with continuous administration of oral enzastaurin until disease progression or unacceptable toxicity. A two-stage sequential design was used to evaluate progression-free survival (PFS) ≥6-months, tumor response, and toxicity. Translational studies included sequencing of the TP53, PTEN, PIK3CA and PKCβII genes for somatic mutations, quantitative PCR assays for AKT2 and PTEN copy number alterations, and measurement of circulating VEGF-A plasma levels. RESULTS Among 27 eligible and evaluable patients, 3 women with PFS≥6-months (11%) and 2 women with partial responses (7%) were observed. One of them achieved a durable response and remains on the study. No grade 4 adverse events were observed. Most common grade 3 adverse events were constitutional (4) and gastrointestinal (3). Mutations in the TP53 gene and abnormal copy number in the PTEN gene were common (56% and 48% of cases, respectively). CONCLUSIONS Enzastaurin was tolerable but had insufficient activity to proceed with the second stage of accrual. However, 1 patient has been progression-free for 44 months. No association between a biomarker and response to enzastaurin has been found. Exploratory analysis suggested an association between survival and PTEN copy number losses.
Collapse
MESH Headings
- Adult
- Aged
- Biomarkers, Tumor/blood
- Carcinoma, Ovarian Epithelial
- Class I Phosphatidylinositol 3-Kinases
- Female
- Genes, p53
- Humans
- Indoles/adverse effects
- Indoles/therapeutic use
- Middle Aged
- Neoplasm Recurrence, Local/blood
- Neoplasm Recurrence, Local/drug therapy
- Neoplasm Recurrence, Local/enzymology
- Neoplasm Recurrence, Local/genetics
- Neoplasms, Glandular and Epithelial/blood
- Neoplasms, Glandular and Epithelial/drug therapy
- Neoplasms, Glandular and Epithelial/enzymology
- Neoplasms, Glandular and Epithelial/genetics
- Ovarian Neoplasms/blood
- Ovarian Neoplasms/drug therapy
- Ovarian Neoplasms/enzymology
- Ovarian Neoplasms/genetics
- PTEN Phosphohydrolase/genetics
- Peritoneal Neoplasms/drug therapy
- Peritoneal Neoplasms/enzymology
- Peritoneal Neoplasms/genetics
- Phosphatidylinositol 3-Kinases/genetics
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/genetics
- Protein Kinase C beta
- Protein Kinase Inhibitors/adverse effects
- Protein Kinase Inhibitors/therapeutic use
- Proto-Oncogene Proteins c-akt/genetics
- Vascular Endothelial Growth Factor A/blood
Collapse
Affiliation(s)
- Lydia Usha
- Department of Medicine, Rush University Medical Center, 1725 West Harrison Street, Chicago, IL 60612, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
von Burstin VA, Xiao L, Kazanietz MG. Bryostatin 1 inhibits phorbol ester-induced apoptosis in prostate cancer cells by differentially modulating protein kinase C (PKC) delta translocation and preventing PKCdelta-mediated release of tumor necrosis factor-alpha. Mol Pharmacol 2010; 78:325-32. [PMID: 20516369 DOI: 10.1124/mol.110.064741] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bryostatin 1, a macrocyclic lactone that has been widely characterized as an ultrapotent protein kinase C (PKC) activator, displays marked pharmacological differences with the typical phorbol ester tumor promoters. Bryostatin 1 impairs phorbol 12-myristate 13-acetate (PMA)-induced tumor promotion in mice and is in clinical trials as an anticancer agent for a number of hematopoietic malignancies and solid tumors. In this study, we characterized the effect of bryostatin 1 on LNCaP prostate cancer cells, a cellular model in which PKC isozymes play important roles in the control of growth and survival. Although phorbol esters promote a strong apoptotic response in LNCaP cells via PKCdelta-mediated release of TNFalpha, bryostatin 1 failed to trigger a death effect even at high concentrations, and it prevented PMA-induced apoptosis in these cells. Mechanistic analysis revealed that bryostatin 1 is unable to induce TNFalpha release, and it impairs the secretion of this cytokine from LNCaP cells in response to PMA. Unlike PMA, bryostatin 1 failed to promote the translocation of PKCdelta to the plasma membrane. Moreover, bryostatin 1 prevented PMA-induced PKCdelta peripheral translocation. Studies using a membrane-targeted PKCdelta construct revealed that the peripheral localization of the kinase is a requisite for triggering apoptosis in LNCaP cells, arguing that mislocalization of PKCdelta may explain the actions of bryostatin 1. The identification of an antiapoptotic effect of bryostatin 1 may have significant relevance in the context of its therapeutic efficacy.
Collapse
Affiliation(s)
- Vivian A von Burstin
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA
| | | | | |
Collapse
|
14
|
Abstract
This review discusses the biosynthesis of natural products that are generated by trans-AT polyketide synthases, a family of catalytically versatile enzymes that have recently been recognized as one of the major group of proteins involved in the production of bioactive polyketides. 436 references are cited.
Collapse
Affiliation(s)
- Jörn Piel
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Bonn, Germany.
| |
Collapse
|
15
|
Sun MK, Alkon DL. Protein kinase C activators as synaptogenic and memory therapeutics. Arch Pharm (Weinheim) 2010; 342:689-98. [PMID: 19899099 DOI: 10.1002/ardp.200900050] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The last decade has witnessed a rapid progress in understanding of the molecular cascades that may underlie memory and memory disorders. Among the critical players, activity of protein kinase C (PKC) isoforms is essential for many types of learning and memory and their dysfunction, and is critical in memory disorders. PKC inhibition and functional deficits lead to an impairment of various types of learning and memory, consistent with the observations that neurotoxic amyloid inhibits PKC activity and that transgenic animal models with PKCbeta deficit exhibit impaired capacity in cognition. In addition, PKC isozymes play a regulatory role in amyloid production and accumulation. Restoration of the impaired PKC signal pathway pharmacologically results in an enhanced memory capacity and synaptic remodeling / repair and synaptogenesis, and, therefore, represents a potentially important strategy for the treatment of memory disorders, including Alzheimer's dementia. The PKC activators, especially those that are isozyme-specific, are a new class of drug candidates that may be developed as future memory therapeutics.
Collapse
Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, Rockville, MD 20850, USA.
| | | |
Collapse
|
16
|
Abstract
Drug discovery from marine natural products has enjoyed a renaissance in the past few years. Ziconotide (Prialt; Elan Pharmaceuticals), a peptide originally discovered in a tropical cone snail, was the first marine-derived compound to be approved in the United States in December 2004 for the treatment of pain. Then, in October 2007, trabectedin (Yondelis; PharmaMar) became the first marine anticancer drug to be approved in the European Union. Here, we review the history of drug discovery from marine natural products, and by describing selected examples, we examine the factors that contribute to new discoveries and the difficulties associated with translating marine-derived compounds into clinical trials. Providing an outlook into the future, we also examine the advances that may further expand the promise of drugs from the sea.
Collapse
|
17
|
Analysis of long-term cognitive-enhancing effects of bryostatin-1 on the rabbit (Oryctolagus cuniculus) nictitating membrane response. Behav Pharmacol 2008; 19:245-56. [DOI: 10.1097/fbp.0b013e3282feb0d2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
Sun MK, Alkon DL. Synergistic effects of chronic bryostatin-1 and α-tocopherol on spatial learning and memory in rats. Eur J Pharmacol 2008; 584:328-37. [DOI: 10.1016/j.ejphar.2008.02.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 01/16/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
|
19
|
Podar K, Raab MS, Chauhan D, Anderson KC. The therapeutic role of targeting protein kinase C in solid and hematologic malignancies. Expert Opin Investig Drugs 2007; 16:1693-707. [PMID: 17922632 DOI: 10.1517/13543784.16.10.1693] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The protein kinase C (PKC) family, the most prominent target of tumor-promoting phorbol esters, is functionally linked to cell differentiation, growth, survival, migration and tumorigenesis and so mediates tumor cell proliferation, survival, multidrug resistance, invasion, metastasis and tumor angiogenesis. Therefore, targeting PKC isozymes may represent an attractive target for novel anticancer therapies. Recent preclinical and clinical studies using the macrocyclic bisindolylmaleimide enzastaurin or the N-benzylstaurosporine midostaurin demonstrate promising activity of PKC inhibitors in a variety of tumors, including diffuse large B-cell lymphoma, multiple myeloma and Waldenstroem's macroglobulinemia. However, our knowledge of PKCs in tumorigenesis is still only partial and each PKC isoform may contribute to tumorigenesis in a distinct way. Specifically, PKC isoforms have vastly different roles, which vary depending on expression levels of organ and tissue distribution, cell type, intracellular localization, protein-protein and lipid-protein interactions and the biologic environment. Although PKC activation generally positively affects tumor cell growth, motility, invasion and metastasis, recent reports show that many PKCs can also have negative effects. Therefore, it is necessary to further dissect the relative contribution of PKC isozymes in the development and progression of specific tumors in order to identify therapeutic opportunities, using either PKC inhibitors or PKC activators.
Collapse
Affiliation(s)
- Klaus Podar
- Dana-Farber Cancer Institute, Department of Medical Oncology, Jerome Lipper Multiple Myeloma Center, 44 Binney Street, Boston, MA 02115, USA.
| | | | | | | |
Collapse
|
20
|
Abstract
Bryostatin-1 is a powerful protein kinase C (PKC) agonist, activating PKC isozymes at nanomolar concentrations. Pharmacological studies of bryostatin-1 have mainly been focused on its action in preventing tumor growth. Emerging evidence suggests, however, that bryostatin-1 exhibits additional important pharmacological activities. In preclinical studies bryostatin-1 has been shown at appropriate doses to have cognitive restorative and antidepressant effects. The underlying pharmacological mechanisms may involve an activation of PKC isozymes, induction of synthesis of proteins required for long-term memory, restoration of stress-evoked inhibition of PKC activity, and reduction of neurotoxic amyloid accumulation and tau protein hyperphosphorylation. The therapeutic potential of bryostatin-1 as a CNS drug should be further explored.
Collapse
Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, Rockville, MD 20850, USA.
| | | |
Collapse
|
21
|
|
22
|
Hotta K, Ueoka H. New cytotoxic agents: a review of the literature. Crit Rev Oncol Hematol 2005; 55:45-65. [PMID: 15927843 DOI: 10.1016/j.critrevonc.2005.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 01/01/2005] [Accepted: 01/28/2005] [Indexed: 10/25/2022] Open
Abstract
The goal of treatment for patients with advanced cancer is to prolong survival, control symptoms, and reduce disease-related complications. Despite the introduction of many cytotoxic agents during the past decade, only modest improvement in survival has been achieved. In order to urgently improve these situations, new cytotoxic agents as well as molecular-targeted agents are now under investigation. In this article, we reviewed the latest information regarding antitumor activity, toxicity, pharmacokinetics, and clinical application of the new cytotoxic agents.
Collapse
Affiliation(s)
- Katsuyuki Hotta
- Health and Environmental Center, Okayama University, 2-1-1, Tsushimanaka, Okayama 700-8530, Japan.
| | | |
Collapse
|
23
|
Elliott MA, Halbert GW. Maintaining the cold chain shipping environment for Phase I clinical trial distribution. Int J Pharm 2005; 299:49-54. [PMID: 15964724 DOI: 10.1016/j.ijpharm.2005.04.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 04/07/2005] [Accepted: 04/23/2005] [Indexed: 11/23/2022]
Abstract
The study aimed to demonstrate satisfactory inter-UK transit of cold storage clinical trial material. The product environment had to be maintained between 0 and 8 degrees C throughout transit until delivery. Straightforward, low cost and simplified shipping arrangements were sought that would be appropriate for small-scale Phase I clinical trial activities. A laboratory test defined an optimal three frozen gel pack configuration to maintain refrigerated environmental conditions for dummy product packs in a single type and size of insulated shipper. The internal environment was temperature monitored at 30-min intervals in all tests. Twelve Glasgow to London transits were then studied over 2 years to include all seasonal temperature variations. A configuration using three frozen gel packs and 4 h pre-chill of the transit container maintained the internal environment at 0-8 degrees C for up to 48 h during autumn, winter and spring. A modified four frozen gel pack configuration was suitable for summer transit. Thus cold shipment verification was successfully carried out for a small-scale distribution operation. It was proven that refrigerated shipping conditions could be maintained using a straightforward and cost effective 'passive' type system consisting of frozen gel packs and insulated transit containers.
Collapse
Affiliation(s)
- M A Elliott
- Phase I/II Clinical Trials Committee Cancer Research UK Formulation Unit, Department of Pharmaceutical Sciences, University of Strathclyde, Glasgow, Scotland G1 1XW, UK.
| | | |
Collapse
|
24
|
Sun MK, Alkon DL. Protein kinase C substrate activators: potential as novel antidepressants. Drug Dev Res 2005. [DOI: 10.1002/ddr.20019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
25
|
Sun MK, Alkon DL. Dual effects of bryostatin-1 on spatial memory and depression. Eur J Pharmacol 2005; 512:43-51. [PMID: 15814089 DOI: 10.1016/j.ejphar.2005.02.028] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Accepted: 02/18/2005] [Indexed: 02/05/2023]
Abstract
Dementia and depression are clinical symptoms commonly associated in patients. Emerging evidence suggests that the two diseases share many profiles in their development and underlying neural/molecular mechanisms. Thus, interest is raised in developing new classes of antidepressant agents with activity of cognitive enhancement. Here, we show that bryostatin-1, a protein kinase C substrate activator, at bilateral intracerebroventricular doses of 0.64 or 2 pmol/site, significantly enhanced learning and memory of rats in a spatial water maze task. When applied at the doses at which it exhibits memory-enhancing activity, bryostatin-1 showed a significant antidepressant activity, as determined in an open space swim test. Both effects were not observed when a smaller dose was administered and were largely eliminated by co-administration of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a protein kinase C inhibitor. These results support the hypothesis that memory processing and mood regulation share common neural mechanisms. Restoring impaired mood regulation with antidepressant agents that also exhibit memory-enhancing activity may represent one of the new strategies in the fight against depression associated with memory impairments.
Collapse
Affiliation(s)
- Miao-Kun Sun
- Blânchette Rockefeller Neurosciences Institute, 9601 Medical Center Drive, Johns Hopkins Academic and Research Building, Room 319, Rockville, MD 20850, USA.
| | | |
Collapse
|
26
|
Affiliation(s)
- Manish A Shah
- Department of Medicine, Division of Solid Tumor Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
| | | |
Collapse
|