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British Journal of Cancer Nov 2018Through several not-fully-characterised moonlighting functions, translation elongation factor eEF1A2 is known to provide a fitness boost to cancer cells. Furthermore,...
BACKGROUND
Through several not-fully-characterised moonlighting functions, translation elongation factor eEF1A2 is known to provide a fitness boost to cancer cells. Furthermore, eEF1A2 has been demonstrated to confer neoplastic characteristics on preneoplastic, nontumourigenic precursor cells. We have previously shown that eEF1A2 is the target of plitidepsin, a marine drug currently in development for cancer treatment. Herein, we characterised a new signalling pathway through which eEF1A2 promotes tumour cell survival.
METHODS
Previously unknown binding partners of eEF1A2 were identified through co-immunoprecipitation, high-performance liquid chromatography-mass spectrometry and proximity ligation assay. Using plitidepsin to release eEF1A2 from those protein complexes, their effects on cancer cell survival were analysed in vitro.
RESULTS
We uncovered that double-stranded RNA-activated protein kinase (PKR) is a novel eEF1A2-interacting partner whose pro-apoptotic effect is hindered by the translation factor, most likely through sequestration and inhibition of its kinase activity. Targeting eEF1A2 with plitidepsin releases PKR from the complex, facilitating its activation and triggering a mitogen-activated protein kinase signalling cascade together with a nuclear factor-κB-dependent activation of the extrinsic apoptotic pathway, which lead to tumour cell death.
CONCLUSIONS
Through its binding to PKR, eEF1A2 provides a survival boost to cancer cells, constituting an Achilles heel that can be exploited in anticancer therapy.
Topics: Animals; Cell Survival; HeLa Cells; Humans; Mice; NF-kappa B; Peptide Elongation Factor 1; Protein Binding; Signal Transduction; eIF-2 Kinase
PubMed: 30420615
DOI: 10.1038/s41416-018-0336-y -
Scientific Reports Jan 2018The design of living cell studies aimed at deciphering the mechanism of action of drugs targeting proteins with multiple functions, expressed in a wide range of...
The design of living cell studies aimed at deciphering the mechanism of action of drugs targeting proteins with multiple functions, expressed in a wide range of concentrations and cellular locations, is a real challenge. We recently showed that the antitumor drug plitidepsin (APL) localizes sufficiently close to the elongation factor eEF1A2 so as to suggest the formation of drug-protein complexes in living cells. Here we present an extension of our previous micro-spectroscopy study, that combines Generalized Polarization (GP) images, with the phasor approach and fluorescence lifetime imaging microscopy (FLIM), using a 7-aminocoumarin drug analog (APL) as fluorescence tracer. Using the proposed methodology, we were able to follow in real time the formation and relative distribution of two sets of APL-target complexes in live cells, revealing two distinct patterns of behavior for HeLa-wt and APL resistant HeLa-APL-R cells. The information obtained may complement and facilitate the design of new experiments and the global interpretation of the results obtained with other biochemical and cell biology methods, as well as possibly opening new avenues of study to decipher the mechanism of action of new drugs.
Topics: Catechin; Drug Discovery; Gene Expression Regulation; HeLa Cells; Humans; Intracellular Space; Microscopy, Fluorescence; Peptide Elongation Factor 1; Protein Binding; Protein Transport
PubMed: 29348621
DOI: 10.1038/s41598-018-19694-3 -
Drug Design, Development and Therapy 2017Plitidepsin is a cyclic depsipeptide that was first isolated from a Mediterranean marine tunicate () and, at present, is manufactured by total synthesis and... (Review)
Review
Plitidepsin is a cyclic depsipeptide that was first isolated from a Mediterranean marine tunicate () and, at present, is manufactured by total synthesis and commercialized as Aplidin. Its antitumor activity, observed in preclinical in vitro and in vivo studies has prompted numerous clinical trials to be conducted over the last 17 years, alone or in combination with other anticancer agents. Single-agent plitidepsin has shown limited antitumor activity and a tolerable safety profile in several malignancies, such as noncutaneous peripheral T-cell lymphoma, melanoma, and multiple myeloma. In patients with relapsed or refractory multiple myeloma, plitidepsin activity seems to be enhanced after addition of dexamethasone while remaining well tolerated, and a Phase III trial comparing plitidepsin plus dexamethasone vs dexamethasone alone is underway. Additional studies are required to better define the role of plitidepsin in combination with other active agents in these indications. Results of plitidepsin activity in other hematological malignancies or solid tumors have been disappointing so far. Further studies analyzing its mechanisms of action and potential biomarkers will help select patients who may benefit most from this drug. In this review, we critically analyze the published studies on plitidepsin in hematological malignancies and solid tumors and discuss its current role and future perspectives in treating these malignancies. We also review its design, pharmaceutical data, and mechanism of action.
Topics: Animals; Antineoplastic Agents, Phytogenic; Depsipeptides; Drug Design; Humans; Neoplasms; Peptides, Cyclic
PubMed: 28176904
DOI: 10.2147/DDDT.S94165 -
Scientific Reports Oct 2016eEF1A2 is one of the isoforms of the alpha subunit of the eukaryotic Elongation Factor 1. It is overexpressed in human tumors and is endowed with oncogenic properties,...
eEF1A2 is one of the isoforms of the alpha subunit of the eukaryotic Elongation Factor 1. It is overexpressed in human tumors and is endowed with oncogenic properties, favoring tumor cell proliferation while inhibiting apoptosis. We demonstrate that plitidepsin, an antitumor agent of marine origin that has successfully completed a phase-III clinical trial for multiple myeloma, exerts its antitumor activity by targeting eEF1A2. The drug interacts with eEF1A2 with a K of 80 nM and a target residence time of circa 9 min. This protein was also identified as capable of binding [C]-plitidepsin in a cell lysate from K-562 tumor cells. A molecular modelling approach was used to identify a favorable binding site for plitidepsin at the interface between domains 1 and 2 of eEF1A2 in the GTP conformation. Three tumor cell lines selected for at least 100-fold more resistance to plitidepsin than their respective parental cells showed reduced levels of eEF1A2 protein. Ectopic expression of eEF1A2 in resistant cells restored the sensitivity to plitidepsin. FLIM-phasor FRET experiments demonstrated that plitidepsin localizes in tumor cells sufficiently close to eEF1A2 as to suggest the formation of drug-protein complexes in living cells. Altogether, our results strongly suggest that eEF1A2 is the primary target of plitidepsin.
Topics: Animals; Antineoplastic Agents; Binding Sites; Cell Line, Tumor; Cell Proliferation; Depsipeptides; HeLa Cells; Humans; Multiple Myeloma; Peptide Elongation Factor 1; Peptides, Cyclic; Protein Domains; Rabbits
PubMed: 27713531
DOI: 10.1038/srep35100 -
BMC Cancer Oct 2015Novel synthesized analogs of Aplidin, PM01215 and PM02781, were tested for antiangiogenic effects on primary human endothelial cells in vitro and for inhibition of...
BACKGROUND
Novel synthesized analogs of Aplidin, PM01215 and PM02781, were tested for antiangiogenic effects on primary human endothelial cells in vitro and for inhibition of angiogenesis and tumor growth in vivo.
METHODS
Antiangiogenic activity of both derivatives was evaluated by real-time cell proliferation, capillary tube formation and vascular endothelial growth factor (VEGF)-induced spheroid sprouting assays. Distribution of endothelial cells in the different phases of the cell cycle was analyzed by flow cytometry. Aplidin analogs were tested in vivo in chicken chorioallantoic membrane (CAM) assays.
RESULTS
Both derivatives inhibited angiogenic capacities of human endothelial cells (HUVECs) in vitro at low nanomolar concentrations. Antiangiogenic effects of both analogs were observed in the CAM. In addition, growth of human multiple myeloma xenografts in vivo in CAM was significantly reduced after application of both analogs. On the molecular level, both derivatives induced cell cycle arrest in G1 phase. This growth arrest of endothelial cells correlated with induction of the cell cycle inhibitor p16(INK4A) and increased senescence-associated beta galactosidase activity. In addition, Aplidin analogs induced oxidative stress and decreased production of the vascular maturation factors Vasohibin-1 and Dickkopf-3.
CONCLUSIONS
From these findings we conclude that both analogs are promising agents for the development of antiangiogenic drugs acting independent on classical inhibition of VEGF signaling.
Topics: Antineoplastic Agents; Blotting, Western; Bortezomib; Cell Cycle; Cell Movement; Cell Proliferation; Depsipeptides; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Humans; Microscopy, Confocal; Multiple Myeloma; Neovascularization, Pathologic; Neovascularization, Physiologic; Oxidative Stress; Peptides, Cyclic; Pregnancy; Tumor Cells, Cultured
PubMed: 26483043
DOI: 10.1186/s12885-015-1729-4 -
Annals of Oncology : Official Journal... Jul 2015Preclinical data have suggested a therapeutic role of JUN pathway activation in dedifferentiated liposarcoma (DDLPS) tumorigenesis. Aplidin is a drug inducing apoptosis...
BACKGROUND
Preclinical data have suggested a therapeutic role of JUN pathway activation in dedifferentiated liposarcoma (DDLPS) tumorigenesis. Aplidin is a drug inducing apoptosis through a strong, sustained activation of c-Jun NH2-terminal kinase.
METHODS
This phase II trial included patients with progressive advanced DDLPS. They received Aplidin 5 mg/m(2) days 1-15, 28-day cycle until disease progression or unacceptable toxicity. The primary end point was the 3-month nonprogression rate (PFS3) defined as the proportion of patients with nonprogressive disease at 3 months. A PFS3 of 40% considered as a reasonable objective to claim drug efficacy.
RESULTS
Between August 2012 and May 2013, 24 patients were included. Sixteen had received prior chemotherapy. Twenty-two were assessable for efficacy. The PFS3 was 9.1% [95% confidence interval (CI) 1.1-29.2]. Median progression-free and overall survivals were 1.6 months (95% CI 1.4-2.6) and 9.2 months (95% CI 6.6-). The most frequent adverse events of any grade were nausea, fatigue, anorexia, vomiting and diarrhea.
CONCLUSION
Aplidin did not meet the primary end point of this trial and do not deserve further investigation in DDLPS.
CLINICALTRIALSGOV IDENTIFIER
NCT01876043.
Topics: Aged; Aged, 80 and over; Depsipeptides; Disease Progression; Female; Follow-Up Studies; Humans; Liposarcoma; Male; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Peptides, Cyclic; Prognosis; Survival Rate
PubMed: 26041763
DOI: 10.1093/annonc/mdv195 -
Blood Cancer Journal Mar 2015Previous data established that plitidepsin, a cyclic depsipeptide, exerted activity in a mouse model of myelofibrosis (MF). New preclinical experiments reported herein...
Evaluation of plitidepsin in patients with primary myelofibrosis and post polycythemia vera/essential thrombocythemia myelofibrosis: results of preclinical studies and a phase II clinical trial.
Previous data established that plitidepsin, a cyclic depsipeptide, exerted activity in a mouse model of myelofibrosis (MF). New preclinical experiments reported herein found that low nanomolar plitidepsin concentrations potently inhibited the proliferation of JAK2V617F-mutated cell lines and reduced colony formation by CD34+ cells of individuals with MF, at least in part through modulation of p27 levels. Cells of MF patients had significantly reduced p27 content, that were modestly increased upon plitidepsin exposure. On these premise, an exploratory phase II trial evaluated plitidepsin 5 mg/m(2) 3-h intravenous infusion administered on days 1 and 15 every 4 weeks (q4wk). Response rate (RR) according to the International Working Group for Myelofibrosis Research and Treatment consensus criteria was 9.1% (95% CI, 0.2-41.3%) in 11 evaluable patients during the first trial stage. The single responder achieved a red cell transfusion independence and stable disease was reported in nine additional patients (81.8%). Eight patients underwent a short-lasting improvement of splenomegaly. In conclusion, plitidepsin 5 mg/m(2) 3-h infusion q4wk was well tolerated but had a modest activity in patients with primary, post-polycythaemia vera or post-essential thrombocythaemia MF. Therefore, this trial was prematurely terminated and we concluded that further clinical trials with plitidepsin as single agent in MF are not warranted.
Topics: Aged; Cell Proliferation; Depsipeptides; Female; Humans; Janus Kinase 2; Male; Middle Aged; Peptides, Cyclic; Polycythemia Vera; Primary Myelofibrosis; Splenomegaly; Thrombocythemia, Essential
PubMed: 25768401
DOI: 10.1038/bcj.2015.5 -
Cancer Treatment Reviews Oct 2014Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas with a very poor prognosis. Current therapies, based on... (Review)
Review
Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas with a very poor prognosis. Current therapies, based on historical regimens for aggressive B-cell lymphomas, have resulted in insufficient patient outcomes. The majority of patients relapse rapidly, and current 5-year overall survival rates are only 10-30%. It is evident that new approaches to treat patients with PTCL are required. In recent years, prospective studies in PTCL have been initiated, mainly in patients with relapsed/refractory disease. In some of these, selected histologic subtypes have been evaluated in detail. As a consequence, numerous new therapies have been developed and shown activity in PTCL, including: agents targeting the immune system (e.g. brentuximab vedotin, alemtuzumab, lenalidomide); histone deacetylase inhibitors (romidepsin, belinostat); antifolates (pralatrexate); fusion proteins (denileukin diftitox); nucleoside analogs (pentostatin, gemcitabine); and other agents (e.g. alisertib, plitidepsin, bendamustine, bortezomib). A variety of interesting novel combinations is also emerging. It is hoped that these innovative approaches, coupled with a greater understanding of the clinicopathologic features, pathogenesis, molecular biology, and natural history of PTCL will advance the field and improve outcomes in this challenging group of diseases. This review summarizes the currently available clinical evidence on the various approaches to treating relapsed/refractory PTCL, including the role of stem cell transplantation, with an emphasis on potential new drug therapies.
Topics: Alemtuzumab; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Brentuximab Vedotin; Cyclophosphamide; Depsipeptides; Diphtheria Toxin; Doxorubicin; Folic Acid Antagonists; Histone Deacetylase Inhibitors; Humans; Immunoconjugates; Interleukin-2; Lenalidomide; Lymphoma, T-Cell, Peripheral; Neoplasm Recurrence, Local; Peptides, Cyclic; Prednisolone; Recombinant Fusion Proteins; Stem Cell Transplantation; Thalidomide; Topoisomerase Inhibitors; Vincristine
PubMed: 25199959
DOI: 10.1016/j.ctrv.2014.08.001 -
Marine Drugs Jan 2014The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or... (Review)
Review
The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or loss of function serve to impart aberrant properties, such as hyperproliferation or inhibition of cell death. However, a tumor is now considered as an organ-like structure, a complex system composed of multiple cell types (e.g., tumor cells, inflammatory cells, endothelial cells, fibroblasts, etc.) all embedded in an inflammatory stroma. All these components influence each other in a complex and dynamic cross-talk, leading to tumor cell survival and progression. As the microenvironment has such a crucial role in tumor pathophysiology, it represents an attractive target for cancer therapy. In this review, we describe the mechanism of action of trabectedin and plitidepsin as an example of how these specific drugs of marine origin elicit their antitumor activity not only by targeting tumor cells but also the tumor microenvironment.
Topics: Animals; Antineoplastic Agents; Aquatic Organisms; Cell Death; Cell Survival; Depsipeptides; Dioxoles; Disease Progression; Humans; Molecular Targeted Therapy; Neoplasms; Peptides, Cyclic; Tetrahydroisoquinolines; Trabectedin; Tumor Microenvironment
PubMed: 24473171
DOI: 10.3390/md12020719 -
British Journal of Cancer Sep 2013This phase I-II trial compared plitidepsin 1-h infusion alone or combined with dacarbazine (DTIC) 1-h infusion as front-line therapy for advanced melanoma. (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
This phase I-II trial compared plitidepsin 1-h infusion alone or combined with dacarbazine (DTIC) 1-h infusion as front-line therapy for advanced melanoma.
METHODS
The recommended dose (RD) for plitidepsin/DTIC was defined in the first stage. In the second stage, patients were randomised to receive single-agent plitidepsin 3.2 mg m(-2) (n = 20) on days 1, 8 and 15 every 4 weeks (q4wk) or plitidepsin 2.4 mg m(-2) on days 1, 8 and 15 q4wk combined with DTIC 800 mg m(-2) q4wk (n = 38).
RESULTS
The overall response rate with plitidepsin/DTIC was 21.4%; all responders had normal serum lactate dehydrogenase (LDH) levels and performance status ≤ 1 at baseline. Median progression-free survival (PFS) with plitidepsin/DTIC was 3.3 months in all patients, and 4.3 months in those with baseline normal LDH. No responses occurred with single-agent plitidepsin and median PFS was 1.5 months. Both regimens were well tolerated. Haematological abnormalities were more common and transaminase increases more severe with plitidepsin/DTIC. Treatment-related transaminase increases leading to infusion omission on day 8 were relatively common. No drug-drug pharmacokinetic interactions were found.
CONCLUSION
This plitidepsin/DTIC schedule has antitumour activity and manageable toxicity in advanced melanoma. Further evaluation of plitidepsin 2.4 mg m(-2) fortnightly and DTIC 800 mg m(-2) q4wk is recommended.
Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Dacarbazine; Depsipeptides; Disease-Free Survival; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Infusions, Intravenous; Male; Melanoma; Middle Aged; Peptides, Cyclic; Treatment Outcome; Young Adult
PubMed: 23989947
DOI: 10.1038/bjc.2013.477