marizomib and Neoplasms

Proteasomes are multisubunit enzyme complexes. They contain three enzymatic active sites which are termed chymotrypsin-like, trypsin-like, and caspase-like. The elementary function of the proteasomes is degradation of damaged proteins. Proteasome inhibition leads to accumulation of damaged protein, which leads to caspase activation and cell death. This relationship is used in cancer therapy. Bortezomib is the first proteasome inhibitor approved by the US Food and Drug Administration for the treatment of relapsed/refractory multiple myeloma. Carfilzomib belongs to the second generation of drugs, which was approved by the US FDA in 2012. Currently in the study phase there are four new inhibitors: ixazomib (MLN9780/MLN2238), delanzomib (CEP-18770), oprozomib (ONX0912/PR-047) and marizomib (NPI-0052).

Topics: Antineoplastic Agents; Apoptosis; Boronic Acids; Bortezomib; Caspases; Dipeptides; Humans; Lactones; Multiple Myeloma; Neoplasms; Oligopeptides; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Proteolysis; Pyrroles; Thiazoles; Threonine

The ubiquitin-proteasome pathway (UPP), which influences essential cellular functions including cell growth, differentiation, apoptosis, signal transduction, antigen processing and inflammatory responses, has been considered as one of the most important cellular protein degradation approaches. Proteasome functions as a gatekeeper, which controls the execution of protein degradation and plays a critical role in the ubiquitin-proteasome pathway. The unfolding of the close connection between proteasome and cancer provides a potential strategy for cancer treatment by using proteasome inhibitors. Small molecular inhibitors of varied structures and potency against proteasome have been discovered in recent years, with bortezomib and carfilzomib having been successfully approved for clinical application while some other promising candidates are currently under clinical trials. Herein, we review the development history of drugs and candidates that target the 20S proteasome, structure-activity relationships (SARs) of various proteasome inhibitors, and related completed or ongoing clinical trials.

Topics: Boron Compounds; Boronic Acids; Bortezomib; Glycine; Humans; Lactones; Neoplasms; Oligopeptides; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Pyrazines; Pyrroles; Structure-Activity Relationship; Threonine

Natural compounds derived from marine organisms have shown a wide variety of anti-tumor effects and a lot of attention has been drawn to further development of the isolated compounds. A vast quantity of individual chemical structures from different organisms has shown a variety of apoptosis inducing mechanisms in a variety of tumor cells. The bis-steroidal cephalostatin 1 for example, induces apoptosis via activation of caspases whereas the polyketide discodermolide inhibits cell growth by binding to and stabilizing microtubule and salisporamide A, the product of an actinobacterial strain, is an inhibitor of the proteasome. This great variety of mechanisms of action can help to overcome the multitude of resistances exhibited by different tumor specimens. Products from marine organisms and their synthetic derivates are therefore an important source for new therapeutics for single agent or combined therapy with other chemotherapeutics to support the struggle against cancer.

Topics: Alkaloids; Alkanes; Animals; Anti-Bacterial Agents; Antineoplastic Agents; Apoptosis; Aquatic Organisms; Biological Products; Bryostatins; Carbamates; Cell Proliferation; Depsipeptides; Dioxoles; Drug Screening Assays, Antitumor; Humans; Lactones; Macrolides; Microtubules; Models, Chemical; Neoplasms; Phenanthrolines; Phenazines; Proteasome Endopeptidase Complex; Pyrones; Pyrroles; Quinolines; Spiro Compounds; Steroids; Tetrahydroisoquinolines; Thiazoles; Trabectedin

The proteasome has emerged as an important clinically relevant target for the treatment of hematologic malignancies. Since the Food and Drug Administration approved the first-in-class proteasome inhibitor bortezomib (Velcade) for the treatment of relapsed/refractory multiple myeloma (MM) and mantle cell lymphoma, it has become clear that new inhibitors are needed that have a better therapeutic ratio, can overcome inherent and acquired bortezomib resistance and exhibit broader anti-cancer activities. Marizomib (NPI-0052; salinosporamide A) is a structurally and pharmacologically unique β-lactone-γ-lactam proteasome inhibitor that may fulfill these unmet needs. The potent and sustained inhibition of all three proteolytic activities of the proteasome by marizomib has inspired extensive preclinical evaluation in a variety of hematologic and solid tumor models, where it is efficacious as a single agent and in combination with biologics, chemotherapeutics and targeted therapeutic agents. Specifically, marizomib has been evaluated in models for multiple myeloma, mantle cell lymphoma, Waldenstrom's macroglobulinemia, chronic and acute lymphocytic leukemia, as well as glioma, colorectal and pancreatic cancer models, and has exhibited synergistic activities in tumor models in combination with bortezomib, the immunomodulatory agent lenalidomide (Revlimid), and various histone deacetylase inhibitors. These and other studies provided the framework for ongoing clinical trials in patients with MM, lymphomas, leukemias and solid tumors, including those who have failed bortezomib treatment, as well as in patients with diagnoses where other proteasome inhibitors have not demonstrated significant efficacy. This review captures the remarkable translational studies and contributions from many collaborators that have advanced marizomib from seabed to bench to bedside.

Topics: Animals; Antineoplastic Agents; Drug Evaluation, Preclinical; Humans; Lactones; Neoplasms; Protease Inhibitors; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Pyrroles

The proteasome is an intracellular enzyme complex that degrades ubiquitin-tagged proteins and thereby regulates protein levels within the cell. Given this important role in maintaining cellular homeostasis, it is perhaps somewhat surprising that proteasome inhibitors have a therapeutic window. Proteasome inhibitors have demonstrated clinical efficacy in the treatment of multiple myeloma and mantle cell lymphoma and are under evaluation for the treatment of other malignancies. Bortezomib is the first and only Food and Drug Administration-approved proteasome inhibitor that inhibits this enzyme complex in a reversible fashion. Although bortezomib improves clinical outcomes when used as a single agent, most patients do not respond to this drug and those who do respond almost uniformly relapse. As such, efforts are underway to develop proteasome inhibitors that act through mechanisms distinct from that of bortezomib. Specifically, inhibitors that bind the active site of the proteasome and inhibit the complex irreversibly have been developed and are in advanced clinical trials. Inhibitors that act on sites of the proteasome outside of the catalytic center have also been identified and are in preclinical development. In this review, we discuss the structure and function of the proteasome. We then focus on the molecular biology, chemistry, and the preclinical and clinical efficacy of novel proteasome inhibitors as strategies to inhibit this target and overcome some forms of bortezomib resistance.

Topics: Allosteric Site; Animals; Antineoplastic Agents; Apoptosis; Boronic Acids; Bortezomib; Cell Line, Tumor; Chloroquine; Clioquinol; Drug Resistance, Neoplasm; Humans; Hydroxyquinolines; Lactones; Neoplasms; Oligopeptides; Protease Inhibitors; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Pyrazines; Pyrroles; Threonine; Ubiquitinated Proteins; Ubiquitination

The salinosporamides are potent proteasome inhibitors among which the parent marine-derived natural product salinosporamide A (marizomib; NPI-0052; 1) is currently in clinical trials for the treatment of various cancers. Methods to generate this class of compounds include fermentation and natural products chemistry, precursor-directed biosynthesis, mutasynthesis, semi-synthesis, and total synthesis. The end products range from biochemical tools for probing mechanism of action to clinical trials materials; in turn, the considerable efforts to produce the target molecules have expanded the technologies used to generate them. Here, the full complement of methods is reviewed, reflecting remarkable contributions from scientists of various disciplines over a period of 7 years since the first publication of the structure of 1.

Topics: Animals; Drug Design; Enzyme Inhibitors; Fermentation; Humans; Lactones; Neoplasms; Proteasome Inhibitors; Pyrroles; Technology, Pharmaceutical

Proteasome inhibitors are rapidly evolving as potent treatment options in cancer therapy. One of the most promising drug candidates of this type is salinosporamide A from the bacterium Salinispora tropica. This marine natural product possesses a complex, densely functionalized γ-lactam-β-lactone pharmacophore, which is responsible for its irreversible binding to its target, the β subunit of the 20S proteasome. Salinosporamide A entered phase I clinical trials for the treatment of multiple myeloma only three years after its discovery. The strong biological activity and the challenging structure of this compound have fueled intense academic and industrial research in recent years, which has led to the development of more than ten syntheses, the elucidation of its biosynthetic pathway, and the generation of promising structure-activity relationships and oncological data. Salinosporamide A thus serves as an intriguing example of the successful interplay of modern drug discovery and biomedical research, medicinal chemistry and pharmacology, natural product synthesis and analysis, as well as biosynthesis and bioengineering.

Topics: Antineoplastic Combined Chemotherapy Protocols; Biological Factors; Cysteine Proteinase Inhibitors; Humans; Lactones; Molecular Conformation; Neoplasms; Proteasome Inhibitors; Pyrroles

The ubiquitin-proteasome pathway functions as a main pathway in intracellular protein degradation and plays a vital role in almost all cellular events. Various inhibitors of this pathway have been developed for research purposes. The recent approval of bortezomib (PS-341, Velcade, a proteasome inhibitor, for the treatment of multiple myeloma has opened the way to the discovery of drugs targeting the proteasome and other components of the ubiquitin-proteasome pathway.. We review the current understanding of the ubiquitin-proteasome pathway and inhibitors targeting this pathway, including proteasome inhibitors, as candidate drugs for chemical therapy.. Preclinical and clinical data for inhibitors of the proteasome and the ubiquitin-proteasome pathway are discussed.. The proteasome and other members in the ubiquitin-proteasome pathway have emerged as novel therapeutic targets.

Topics: Acetylcysteine; Animals; Antineoplastic Agents; Biological Products; Boronic Acids; Bortezomib; Drug Delivery Systems; Drug Discovery; Humans; Lactones; Neoplasms; Peptides; Protease Inhibitors; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Pyrazines; Pyrroles; Structure-Activity Relationship; Ubiquitin; Ubiquitin-Activating Enzymes; Ubiquitins

Ubiquitin (Ub) is a small protein modifier involved in cellular functions such as cell cycle, apoptosis, cell signalling, endocytosis, transcription and DNA repair. Ubiquitin operates as a reversible and highly versatile regulatory signal, which may be read and interpreted by an expanding number of Ub-binding domains (UBD). There is accumulating evidence that mutations or altered expression of ubiquitylating or de-ubiquitylating enzymes as well as of Ub-binding proteins affect crucial mediators of such functions and are found in several malignancies. Here we discuss how oncogenic alterations in the Ub system can be targeted by anti-cancer therapies.

Topics: Antineoplastic Agents; Boronic Acids; Bortezomib; Cell Communication; Cell Cycle; Genetic Therapy; Heat-Shock Proteins; Humans; Lactones; Neoplasms; Pyrazines; Pyrroles; Ubiquitin

Marizomib (NPI-0052) is an irreversible proteasome inhibitor, derived from a marine actinomycete, with activity and specificity that is distinct from other proteasome inhibitors.. Phase I study (NPI-0052-102) evaluated the MTD, pharmacokinetics, and pharmacodynamics of marizomib intravenously on two dosing schedules.. Forty-two patients with advanced malignancies received Schedule A (0.1-0.9 mg/m(2) over 1-10 minutes on days 1, 8, 15 in 4-week cycles); 44 patients with relapsed and/or refractory multiple myeloma (RRMM) and other hematologic malignancies received Schedule B (0.075-0.6 mg/m(2) over 1 minute to 2 hours on days 1, 4, 8, 11, in 3-week cycles). The Schedule A recommended phase II dose was 0.7 mg/m(2) over 10 minutes; Schedule B was 0.5 mg/m(2) over 2 hours. The most common (>25% of patients) related adverse events were fatigue, nausea, diarrhea, and infusion site pain (Schedule A); and fatigue (Schedule B). Overall response rate of 11% was seen in 27 efficacy-evaluable RRMM Schedule B patients (1 very good partial response, 3 partial responses, 4 minimal responses, and 12 stable disease). One Schedule A patient with transformed marginal zone lymphoma had complete response. Marizomib has a short half-life (<30 minutes), with high volume of distribution (∼15-416 L) and clearance (∼0.9-22 L/minutes).. Marizomib does not exhibit the severe peripheral neuropathy or hematologic toxicity observed with other proteasome inhibitors. Marizomib was generally well tolerated with low-dose dexamethasone, demonstrated activity in heavily pretreated RRMM patients, and warrants further evaluation. Clin Cancer Res; 22(18); 4559-66. ©2016 AACR.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Drug Administration Schedule; Female; Humans; Lactones; Male; Middle Aged; Multiple Myeloma; Neoplasm Staging; Neoplasms; Proteasome Inhibitors; Pyrroles; Recurrence; Retreatment; Treatment Outcome; Young Adult

TRAIL promotes apoptotic tumor cell death; however, TRAIL-resistant tumors need to be sensitized to reverse resistance. Proteasome inhibitors potentiate TRAIL apoptosis in vitro and in vivo and correlate with up-regulation of death receptor 5 (DR5) via an unknown mechanism. We hypothesized that the proteasome inhibitor NPI-0052 inhibits the transcription repressor Yin Yang 1 (YY1) which regulates TRAIL resistance and negatively regulates DR5 transcription. Treatment of PC-3 and Ramos cells with NPI-0052 (

Topics: Apoptosis; Boronic Acids; Bortezomib; Cell Line, Tumor; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Hematopoietic Stem Cells; Humans; Lactones; Neoplasms; NF-kappa B; Protease Inhibitors; Pyrazines; Pyrroles; Receptors, TNF-Related Apoptosis-Inducing Ligand; RNA, Messenger; RNA, Small Interfering; TNF-Related Apoptosis-Inducing Ligand; Transcription, Genetic; Up-Regulation; YY1 Transcription Factor