plitidepsin and Multiple-Myeloma

Plitidepsin is a marine-derived anticancer compound isolated from the Mediterranean tunicate Applidium albicans. It exerts pleiotropic effects on cancer cells, most likely by binding to the eukaryotic translation eEF1A2. This ultimately leads to cell-cycle arrest, growth inhibition and induction of apoptosis via multiple pathway alterations. Recently, a Phase III randomized trial in patients with relapsed/refractory multiple myeloma reported outcomes for plitidepsin plus dexamethasone compared with dexamethasone. Median progression-free survival was 3.8 months in the plitidepsin arm and 1.9 months in the dexamethasone arm (HR: 0.611; p = 0.0048). Here, we review preclinical data regarding plitidepsins mechanism of action, give an overview of clinical trial results across different tumor types as well as the latest results in multiple myeloma.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Aquatic Organisms; Clinical Trials, Phase III as Topic; Depsipeptides; Dexamethasone; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Humans; Multiple Myeloma; Neoplasm Recurrence, Local; Peptide Elongation Factor 1; Peptides, Cyclic; Progression-Free Survival; Randomized Controlled Trials as Topic; Urochordata

The outcome of multiple myeloma has substantially improved over the past decade, mainly due to recently approved drugs, such as thalidomide, lenalidomide, and bortezomib. Nevertheless, most patients still relapse and, therefore, drugs with new mechanisms of action are urgently needed to overcome this resistance. In this Review, we discuss some of the new targeted therapeutic strategies under assessment in preclinical and clinical studies in multiple myeloma. Unfortunately, the single-agent clinical activity of most of these new drugs has been limited; nevertheless, their effectiveness might be enhanced by their rational combination with each other or with conventional agents.

Topics: Antibodies, Monoclonal; Antigens, Surface; Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Cell Cycle; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Cysteine Proteinase Inhibitors; Depsipeptides; DNA Methylation; Enzyme Inhibitors; Epigenesis, Genetic; Farnesyl-Diphosphate Farnesyltransferase; Heat-Shock Proteins; Histone Deacetylase Inhibitors; Humans; Mitogen-Activated Protein Kinase Kinases; Multiple Myeloma; NF-kappa B; Oligopeptides; Oxides; Peptides, Cyclic; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Receptor Protein-Tyrosine Kinases; Receptors, Cell Surface; Signal Transduction; TOR Serine-Threonine Kinases

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Bortezomib; Depsipeptides; Dexamethasone; Disease-Free Survival; Female; Humans; Lenalidomide; Male; Middle Aged; Multiple Myeloma; Peptides, Cyclic; Survival Rate; Thalidomide

This trial evaluated the antitumor activity and safety of the marine-derived cyclodepsipeptide plitidepsin in patients with relapsed/refractory multiple myeloma.. This was a prospective, multicenter, open-label, single-arm, phase II trial with plitidepsin at 5 mg/m(2) as a 3-hour i.v. infusion every two weeks. The protocol was amended to allow patients with suboptimal response to single-agent plitidepsin to add 20 mg/day on days 1 to 4 of oral dexamethasone every two weeks.. Fifty-one patients started treatment with plitidepsin and 47 were evaluable for efficacy. The overall response rate (complete response plus partial response plus minimal response) was 13% with plitidepsin alone and 22% in the cohort of patients with the addition of dexamethasone (n = 19, 18 evaluable). Both plitidepsin alone and with dexamethasone were feasible and well tolerated. Anemia (29%) and thrombocytopenia (18%) were the most frequent grade 3/4 hematologic toxicities. Fatigue (16%), muscular toxicity (6%), and transient alanine aminotransferase/aspartate aminotransferase (27%) and creatine phosphokinase (23%) increases were the most relevant nonhematologic side effects. A prolonged plasma half-life was observed in responding patients as compared with nonresponding patients (P = 0.009).. Single-agent plitidepsin has limited but reproducible activity in relapsed/refractory multiple myeloma patients. Activity observed after dexamethasone addition merits further study. Both regimens were well tolerated in this heavily pretreated population.

Topics: Aged; Aged, 80 and over; Anemia; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Depsipeptides; Dexamethasone; Drug Administration Schedule; Drug Resistance, Neoplasm; Fatigue; Female; Humans; Male; Middle Aged; Multiple Myeloma; Peptides, Cyclic; Recurrence

Plitidepsin (PLD, Aplidin®), a cyclic depsipeptide originally isolated from the marine tunicate Aplidium albicans, has been recently approved by Australian regulatory authorities for the treatment of multiple myeloma patients. Plitidepsin binds to eEF1A2 and induces oxidative stress, Rac1 activation and JNK1 phosphorylation, triggering a rapid apoptotic program in tumor cells. Since oxidative stress is one of the known sources of endoplasmic reticulum stress, we investigated whether PLD was inducing a bona fide ER stress in HeLa cells and whether this process was essential in the mechanism of action of the compound. Indeed, PLD activated an ER stress-induced unfolded protein response (UPR), including the alternative splicing of XBP1, the proteolytic processing of ATF6 and the phosphorylation of eIF2α and JNK. Interestingly, though PLD induced a strong phosphorylation of eIF2α in all the analyzed cell lines, it did not elicit an increased expression of ATF4 and CHOP, a transcription factor involved in launching UPR-mediated apoptosis. On the contrary, a clear reduction of CHOP protein levels was observed after PLD treatment, most probably due to both the lack of transactivation by ATF4 and its rapid degradation by the ubiquitin/proteasome machinery. Using fibroblasts devoid of each one of the four possible kinases involved in eIF2α phosphorylation, we observed that only PKR was involved in the response to PLD treatment and, accordingly, PKR

Topics: Animals; Antineoplastic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Depsipeptides; Endoplasmic Reticulum Stress; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Mice, SCID; Multiple Myeloma; Neoplasms, Experimental; Oxidative Stress; Peptides, Cyclic; Phosphorylation; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Transcription Factor CHOP

While remaining relatively rare, multiple myeloma (MM) accounts for approximately 10% of all hematological malignancies, being an insidious disease with an overall 5-year survival rate of 52%. In addition to other associated complications, myeloma bone disease further aggravates MM patients, the majority of whom suffer from lytic lesions, leading to pain, fractures, mobility issues and neurological deficits. Patients not responding or becoming resistant to prior therapies have now a novel therapeutic tool with an unprecedent mode of action, differing from those currently in use. The anticancer effects of the marine-derived antitumor agent plitidepsin primarily rely on the interaction with elongation factor 1-α 2 (eEF1A2), known to be overexpressed in breast cancer and MM cells, targeting the noncanonical role of the protein and leading to a proapoptotic response. Following the drug's approval from Australian regulatory authorities, eligible patients will have access to a new first-in-class drug to treat MM, expanding the current anti-MM portfolio. Plitidepsin (Aplidin; PharmaMar) was approved in combination with the corticosteroid agent dexamethasone, to treat MM patients who failed or became resistant to other therapies, covering the third- and fourth-line treatment setting.

Topics: Antineoplastic Agents; Australia; Depsipeptides; Humans; Multiple Myeloma; Peptide Elongation Factor 1; Peptides, Cyclic

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

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

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.. 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.. 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.. 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

Aplidin is an antitumour drug, currently undergoing phase II evaluation in different haematological and solid tumours. In this study, we analysed the antimyeloma effects of Aplidin in the syngeneic 5T33MM model, which is representable for the human disease. In vitro, Aplidin inhibited 5T33MMvv DNA synthesis with an IC(50) of 3.87 nM. On cell-cycle progression, the drug induced an arrest in transition from G0/G1 to S phase, while Western blot showed a decreased cyclin D1 and CDK4 expression. Furthermore, Aplidin induced apoptosis by lowering the mitochondrial membrane potential, by inducing cytochrome c release and by activating caspase-9 and caspase-3. For the in vivo experiment, 5T33MM-injected C57Bl/KaLwRij mice were intraperitoneally treated with vehicle or Aplidin (90 microg kg(-1) daily). Chronic treatment with Aplidin was well tolerated and reduced serum paraprotein concentration by 42% (P<0.001), while BM invasion with myeloma cells was decreased by 35% (P<0.001). Aplidin also reduced the myeloma-associated angiogenesis to basal values. This antiangiogenic effect was confirmed in vitro and explained by inhibition of endothelial cell proliferation and vessel formation. These data indicate that Aplidin is well tolerated in vivo and its antitumour and antiangiogenic effects support the use of the drug in multiple myeloma.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Blotting, Western; Cell Cycle; Depsipeptides; Disease Models, Animal; DNA Replication; Mice; Mice, Inbred C57BL; Multiple Myeloma; Peptides, Cyclic; Rats

Despite recent progress in its treatment, multiple myeloma (MM) remains incurable, thus necessitating identification of novel anti-MM agents. We report that the marine-derived cyclodepsipeptide Aplidin exhibits, at clinically achievable concentrations, potent in vitro activity against primary MM tumor cells and a broad spectrum of human MM cell lines, including cells resistant to conventional (e.g., dexamethasone, alkylating agents, and anthracyclines) or novel (e.g., thalidomide and bortezomib) anti-MM agents. Aplidin is active against MM cells in the presence of proliferative/antiapoptotic cytokines or bone marrow stromal cells and has additive or synergistic effects with some of the established anti-MM agents. Mechanistically, a short in vitro exposure to Aplidin induces MM cell death, which involves activation of p38 and c-jun NH(2)-terminal kinase signaling, Fas/CD95 translocation to lipid rafts, and caspase activation. The anti-MM effect of Aplidin is associated with suppression of a constellation of proliferative/antiapoptotic genes (e.g., MYC, MYBL2, BUB1, MCM2, MCM4, MCM5, and survivin) and up-regulation of several potential regulators of apoptosis (including c-JUN, TRAIL, CASP9, and Smac). Aplidin exhibited in vivo anti-MM activity in a mouse xenograft model. The profile of the anti-MM activity of Aplidin in our preclinical models provided the framework for its clinical testing in MM, which has already provided favorable preliminary results.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow Cells; Cell Line, Tumor; Cell Survival; Coculture Techniques; Depsipeptides; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Insulin-Like Growth Factor I; Interleukin-6; Mice; Mice, SCID; Multiple Myeloma; Oligonucleotide Array Sequence Analysis; Peptides, Cyclic; Seawater; Stromal Cells; Time Factors; Treatment Outcome; Urochordata; Xenograft Model Antitumor Assays