Trabectedin: ET 743, ecteinascidin 743, Yondelis.
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Advanced sarcomas have a poor prognosis and limited therapeutic options. Disease recurrence is caused by persistent cells that survive drug treatments. The alkylating agent trabectedin, when combined with the poly (ADP-ribose) polymerase 1 (PARP1) inhibitor olaparib, exhibits variable antitumor effects in advanced sarcomas. In this study, we demonstrate that the expression of the transcription factor OCT4 is upregulated in persistent cells that survive treatment with trabectedin and olaparib, through the cGAS-STING-IRF3-IFNβ pathway. This route also leads to the upregulation of natural killer (NK) and cytokine-induced killer (CIK) lymphocyte activating ligands. These molecular events enhance the antitumor efficacy of immunotherapy with NK and CIK cells, targeting both the bulk population and residual drug-tolerant cells. In conclusion, the activation of the cGAS-STING pathway has a double-edged effect, enriching the OCT4+ persistent cell population while increasing the expression of NK/CIK ligands. The addition of olaparib to trabectedin potentiates the cGAS-STING pathway activation and the upregulation of NKG2DLs, while simultaneously counteracting the OCT4 overexpression. Therefore, sequential treatment with trabectedin and olaparib followed by NK/CIK immunotherapy represents a promising strategy against advanced sarcomas and warrants further investigation.
IMPORTANCE: Leiomyosarcoma is a rare and heterogeneous malignant mesenchymal neoplasm associated with substantial morbidity and mortality. Given recent advances in biologic understanding and the complexity of leiomyosarcoma, a consensus-driven approach is needed to harmonize management and address remaining clinical and research gaps. OBJECTIVE: To provide an evidence-based synthesis of current diagnostic and therapeutic approaches for leiomyosarcoma by an international panel of physicians, researchers, and patient advocates, focusing on site-specific management, systemic therapy strategies, and key areas of clinical uncertainty, while identifying unmet needs and research priorities. EVIDENCE REVIEW: This review is based on a comprehensive evaluation of the literature, including clinical trials, observational studies, and international consensus guidelines. Sources were identified through MEDLINE (via PubMed) and Embase database searches and reference screening, then supplemented by multidisciplinary expert consensus. Emphasis was placed on studies informing diagnosis, surgical management, radiotherapy, and systemic therapy in leiomyosarcoma. FINDINGS: The rarity and heterogeneity of leiomyosarcoma poses substantial challenges in its management. In localized disease, complete surgical resection remains the cornerstone of treatment, with evidence supporting the use of site-specific perioperative treatment strategies. Prospective data supporting neoadjuvant or adjuvant chemotherapy are lacking, and the role of radiotherapy differs across anatomic disease sites and institutions. In advanced disease, multiple systemic therapies demonstrate activity, including anthracycline-based and gemcitabine-based combinations, trabectedin, and tyrosine kinase inhibitors, although optimal sequencing after first-line therapy remains undefined. Emerging data suggest potential benefit from treatment continuation strategies and selected use of local therapies in oligometastatic settings. Molecular heterogeneity is increasingly recognized but has not yet translated into routine clinical implementation, and integration of molecular profiling into diagnostic pathways for predictive and therapeutic insights remains an unmet need. CONCLUSIONS AND RELEVANCE: This international consensus addresses the diagnosis and management of leiomyosarcoma. Management requires a multidisciplinary, site-specific approach informed by limited but evolving evidence. Key uncertainties persist, particularly regarding perioperative therapy, optimal sequencing and combination of systemic treatments, and integration of molecular data. Continued international collaboration and leiomyosarcoma-specific clinical trials are needed to refine treatment strategies and improve patient outcomes.
A method was developed for the bio-analysis of Ecteinascidin 743 (ET-743) using miniaturized liquid chromatography (LC) coupled to an electrospray ionization sample inlet (TurbolonSpray) and two quadrupole mass analyzers (LC/ESI-MS/MS). Solid-phase extraction was used as a sample pretreatment procedure. Ecteinascidin 743 is a very potent anticancer compound and is administered in microgram m-2 dosages, which demands special requirements in terms of sensitivity for the analytical method supporting clinical pharmacokinetic studies. Using conventional LC/UV, a lower limit of quantitation (LLQ) of 1 ng ml-1 plasma was reached using a 500 microliters sample volume, but LC/ESI-MS/MS permitted an LLQ of 10 pg ml-1. The latter method was found to be accurate and precise, and provided a broad linear concentration range of 0.010-2.50 ng ml-1.
The cytotoxic activity of ecteinascidin 743 (ET-743), a natural product derived from the marine tunicate Ecteinascidia turbinata that exhibits potent anti-tumor activity in pre-clinical systems and promising activity in phase I and II clinical trials, was investigated in a number of cell systems with well-defined deficiencies in DNA-repair mechanisms. ET-743 binds to N2 of guanine in the minor groove, but its activity does not appear to be related to DNA-topoisomerase I poisoning as the drug is equally active in wild-type yeast and in yeast with a deletion in the DNA-topoisomerase I gene. Defects in the mismatch repair pathway, usually associated with increased resistance to methylating agents and cisplatin, did not affect the cytotoxic activity of ET-743. However, ET-743 did show decreased activity (from 2- to 8-fold) in nucleotide excision repair (NER)-deficient cell lines compared to NER-proficient cell lines, from either hamsters or humans. Restoration of NER function sensitized cells to ET-743 treatment. The DNA double-strand-break repair pathway was also investigated using human glioblastoma cell lines MO59K and MO59J, respectively, proficient and deficient in DNA-dependent protein kinase (DNA-PK). ET-743 was more effective in cells lacking DNA-PK; moreover, pre-treatment of HCT-116 colon carcinoma cells with wortmannin, a potent inhibitor of DNA-PK, sensitized cells to ET-743. An increase in ET-743 sensitivity was also observed in ataxia telangiectasia-mutated cells. Our data strongly suggest that ET-743 has a unique mechanism of interaction with DNA.
Ecteinascidin 743 (Et 743), a natural product derived from the Caribbean tunicate Eteinascidia turbinata, is a potent antitumor agent currently in phase II clinical trials. Et 743 binds in the minor groove of DNA, forming covalent adducts by reacting with N2 of guanine. Although DNA is considered to be the macromolecular receptor for Et 743, the precise mechanism by which Et 743 exerts its remarkable antitumor activity has not yet been elucidated. The aim of this study is to provide a rationale for the antitumor activity of Et 743 by studying its fundamental interactions with DNA at the molecular level. First, DNA structural distortions induced by Et 743 were characterized using gel electrophoresis. Surprisingly, Et 743 bends DNA toward the major groove, a unique feature among DNA-interactive agents that occupy the minor groove. Second, in order to gain further insight into the molecular basis behind the apparent sequence selectivity of Et 743, the stability and structure of Et 743 adducts at different target sequences were determined. On the basis of this data, the overall stability of the Et 743-DNA adducts was found to be governed by the DNA target sequence, where the inability of Et 743 to form optimum bonding networks with its optimum recognition sites leads to the formation of an unstable adduct. Consequently, the reaction of Et 743 with DNA is reversible, and the rate of the reverse reaction is a function of the target and flanking sequences. The results from this study demonstrate that Et 743 differs from other DNA alkylating agents by its effects on DNA structure and sequence-dependent chemical stability. This information provides important insight into the underlying mechanisms for its unique profile of antitumor activity.
PURPOSE: Ecteinascidin 743 (ET-743) is a potent cytotoxic alkaloid of marine origin that has shown promising evidence of antitumor activity during phase I clinical trials. In the study reported here, the influence of clinical characteristics and pretreatment pathophysiological variables on the pharmacokinetics of ET-743 and their associations with drug-related toxicity was examined in sarcoma patients treated in three phase II clinical trials. METHODS: Adult patients with various histological subtypes of soft tissue sarcoma received 1.5 mg/m(2) of ET-743 by 24-h continuous i.v. infusion once every 3 weeks. Eligibility criteria were similar for each study, except for the histological subtype of the tumor or the extent of prior treatment with other anticancer agents, and all patients had normal or near-normal liver and renal function. The maximum plasma concentration (C(max)) and area under the plasma profile from time zero to infinity (AUC) of the drug were determined during the first cycle of therapy. Patients were evaluated for toxicity every week. RESULTS: Geometric mean +/- SD values of the pharmacokinetic parameters in 69 patients were: C(max) 1.14 +/- 0.52 ng/ml, AUC 39.9 +/- 16.6 ng.h/ml, and total body clearance (CL) 36.7 +/- 16.4 l/h per m(2). The only significant correlation involving physical characteristics of the patients or pretreatment pathophysiological variables was a very weak relationship between alkaline phosphatase and AUC (r=0.39, P<0.01). The 15 patients with any baseline liver function test exceeding the upper limit of the normal ranges had a significantly greater (P=0.02) incidence of severe toxicity (80% vs 44%). Although the mean AUC of ET-743 in patients with elevated serum levels of hepatic enzymes was 17% greater than that in patients with normal pretreatment liver function tests, the difference was not significant ( P=0.22). In addition, there was no distinct relationship between the grade of the most severe drug-related toxicity that occurred during the first cycle of therapy and the AUC for the entire cohort. The CL of ET-743 was found to be 27% greater in patients concurrently receiving dexamethasone as a preventative antiemetic than in those who were not, but the difference did not achieve statistical significance (P=0.08). There were no significant associations between CL (liters per hour) and body surface area or any other variable related to body size. CONCLUSIONS: The risk of developing severe toxicity was substantially enhanced in patients with relatively moderate indications of hepatic dysfunction without a coincident effect on the CL of ET-743. Dexamethasone cotreatment appeared to decrease the incidence of severe toxicity as well as the AUC of the drug. Delivering a fixed amount of drug without adjustment for the height or weight of the patient may be more appropriate than dose normalization due to the absence of an association between CL and body surface area. Optimizing dosing strategies to further enhance the therapeutic index of ET-743 may depend upon obtaining a better understanding of the metabolic fate of the drug in humans.
PURPOSE: Ecteinascidin 743 (ET-743) is a novel, marine-derived anticancer agent currently under clinical development for the treatment of solid tumors. The aim of this study was to develop and validate limited sampling strategies for the prediction of ET-743 clearance in phase II studies, using two techniques: the stepwise linear regression approach and the Bayesian estimation approach. METHODS: Data from a phase I dose-finding study were used with ET-743 administered as a 24-h infusion. Plasma concentration time data from 34 patients treated with 1200. 1500 or 1800 microg/m2 ET-743 were randomly divided into an index data set, used for the development of the strategies, and a validation data set. With the linear regression approach, clearance (obtained by non-compartmental analysis) was correlated with the ratios of dose to the observed concentrations. For the Bayesian approach a three-compartment population pharmacokinetic model was developed; optimal time-points were selected using the D-optimality algorithm. The strategies were compared by assessment of their predictive performance of CL in the validation data set. RESULTS: The linear regression method yielded a single-point sampling schedule with no significant bias and acceptable precision (-0.03% and 21%, respectively). With the Bayesian approach, a three-sample strategy was selected which resulted in less-accurate, but unbiased, predictions (bias 13%, precision 34%). CONCLUSIONS: Optimal sampling strategies were developed and validated for estimation of ET-743 clearance. Although the linear regression approach showed slightly better predictive performance, the Bayesian approach is preferred for the current phase II studies as it is more robust and flexible and allows the description of the full pharmacokinetic profile.
The shellfish toxin, okadaic acid (OA), is a potent tumor promoter that induces expression of the proto-oncogene junB in mouse keratinocyte 308 cells. Here we show, through deletion analysis of the junB promoter, that sequences near the TATA box conferred transcriptional induction by OA. Transient transfections of luciferase constructs bearing the junB promoter with single mutations in various cis elements demonstrated that a promoter containing a mutated CCAAT box could not be induced by OA. When this CCAAT box was inserted into a heterologous promoter construct, OA induction was dependent on an intact CCAAT box. Flanking cis elements located near the CCAAT box, although not required for OA inducibility, did play a role in the basal level of transcription. NF-Y was shown by EMSA to bind to the CCAAT box. OA induction from the junB CCAAT box was blocked by dominant negative NF-YA as well as the CCAAT box-dependent anticancer drug, ET-473. Expression of a lexA/NF-YA chimeric protein demonstrated that OA induction was dependent on the binding of NF-Y family members. These studies demonstrate that OA can mediate transcriptional activation of junB through the classical CCAAT box and that transcription factor NF-Y plays a functional role in the induction.
A reversed-phase high-performance liquid chromatographic method has been developed and validated for the quantification of the novel anticancer drug Ecteinascidin 743 in human plasma. The sample pretreatment of the plasma samples involved a solid-phase extraction (SPE) on cyano columns. Propyl-p-hydroxybenzoate was added after the sample pretreatment to correct for variability in injection volumes. The separation was performed on a Zorbax SB-C18 column (75x4.6 mm I.D., particle size 3.5 microm) with acetonitrile-25 mM phosphate buffer, pH 5.0 (70:30, v/v) as the mobile phase. The flow-rate was 1.0 ml/min and the eluent was monitored at 210 nm. The accuracies and precisions of the assay fall within +/-15% for all quality control samples and within +/-20% for the lower limit of quantitation, which was 1.0 ng/ml using 500 microl of plasma. The overall recovery of the sample pretreatment procedure for Ecteinascidin 743 was 87.0+/-5.9%. The drug was found to be stable in human plasma at -30 degrees C for at least 2 months. At room temperature Ecteinascidin 743 was stable in human plasma for 5 h at most.
The mode of action of Ecteinascidin-743 (ET-743), a marine tetrahydroisoquinoline alkaloid isolated from Ecteinascidia turbinata, which has shown very potent antitumour activity in preclinical systems and encouraging results in Phase I clinical trials was investigated at a cellular level. Both SW620 and LoVo human intestinal carcinoma cell lines exposed for 1 h to ET-743 progress through S phase more slowly than control cells and then accumulate in the G2M phase. The sensitivity to ET-743 of G1 synchronised cells was much higher than that of cells synchronised in S phase and even higher than that of cells synchronised in G2M. ET-743 concentrations up to four times higher than the IC(50) value caused no detectable DNA breaks or DNA-protein cross-links as assessed by alkaline elution techniques. ET-743 induced a significant increase in p53 levels in cell lines expressing wild-type (wt) (p53). However, the p53 status does not appear to be related to the ET-743 cytotoxic activity as demonstrated by comparing the drug sensitivity in p53 (-/-) or (+/+) mouse embryo fibroblasts and in A2780 ovarian cancer cells or the A2780/CX3 sub-line transfected with a dominant-negative mutant TP53. The cytotoxic potency of ET-743 was comparatively evaluated in CHO cell lines proficient or deficient in nucleotide excision repair (NER), and it was found that ET-743 was approximately 7-8 times less active in ERCC3/XPB and ERCC1-deficient cells than control cells. The findings that G1 phase cells are hypersensitive and that NER-deficient cells are resistant to ET-743 indicate that the mode of action of ET-743 is unique and different from that of other DNA-interacting drugs.
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Ecteinascidine-743 (ET-743) and aplidine are two marine-derived antineoplastics currently in phase II development. With the aim of evaluating whether in vitro haematopoietic studies can predict the toxicity of these two drugs in patients, human bone marrow (BM) samples were incubated with these drugs under conditions which mimicked the administration exposures used in the clinics. As it was observed in different cancer cell lines, ET-743 was more toxic on an equimolar basis in human hematopoietic progenitors (inhibitory concentration reducing the viability to 50% after 24 h exposures; IC50(24h): 10-50 nM) compared with doxorubicin (IC50(24h) values: 280-460 nM), used as a control anticancer drug. In contrast to the high haematotoxic effects observed for ET-743, similar IC values were obtained for aplidine (IC50(24h): 150-530 nM) compared with doxorubicin. For both ET-743 and aplidine, the megakaryocytic progenitor was the most sensitive, compared with the other haematopoietic progenitors (IC50 values were 3- to 5-fold lower in the CFU-Megs compared with the CFU-GMs). The observation that the Cmax observed in patients treated with the aplidine maximum tolerated dose (MTD) (7.1 nM) was 21-75 fold lower than the IC50(24h) value observed for the different haematopoietic progenitors is highly consistent with the lack of haematotoxicity observed in patients treated with this drug. In the case of ET-743, differences between the Cmax value corresponding to the MTD (2.6 nM) and the in vitro IC50 values corresponding to the different progenitors were much lower (4-19-fold), also consistent with the haematotoxicity that was observed in patients treated at recommended doses (RDs) and MTDs. Although CFU-Megs were more sensitive than CFU-GM progenitors to ET-743 in vitro, clinical data showed that neutropenic events were more frequent than thrombocytopenic episodes. Aiming to further improve the predictive value of in vitro IC values corresponding to the different haematopoietic progenitors, additional refinement parameters derived from pharmacokinetic and animal studies are proposed.
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BACKGROUND: Ecteinascidin 743 (Et 743), a natural product derived from a marine tunicate, is a potent antitumor agent presently in phase II clinical trials. Et 743 binds in the minor groove of DNA and alkylates N2 of guanine via a unique mechanism involving catalytic activation. The sequence selectivity of Et 743 is governed by different patterns of hydrogen-bonding to DNA, which results in differential reversibility of the covalent adducts. As determined by nuclear magnetic resonance spectroscopy, the preferred sequences 5'-PuGC and 5'-PyGG are stabilized by a hydrogen-bonding network, while the non-preferred sequences 5'-NG(A/T) are much less stabilized due to the lack of a key hydrogen bond to the GC base pair on the 3'-side of the alkylated guanine. RESULTS: Mammalian cell lines (XPB, XPD, XPF, XPG, and ERCC1) deficient in the nucleotide excision repair (NER) gene products show resistance to Et 743. The recognition and subsequent incision of Et 743-DNA adducts by the bacterial multisubunit endonuclease UvrABC were used to evaluate DNA repair-mediated toxicity as a rationale for the resistance of NER-defective cell lines and the antitumor activity of Et 743. The Et 743-DNA adducts are indeed recognized and incised by the UvrABC repair proteins; however, the pattern of incision indicated that the non-preferred, and less stable, sequences (i.e. 5'-NG(A/T)) modified with Et 743 are generally incised at a much higher efficiency than the preferred, more stable sequences (i.e. 5'-PuGC or 5'-PyGG). In addition, within the same Et 743 recognition sequence, the level of incision varies, indicating that flanking regions also contribute to the differential incision frequency. CONCLUSIONS: The inefficient repair incision by the UvrABC nuclease of Et 743-DNA adducts provides a basis for rationalizing the observed repair-dependent cytotoxicities of these DNA adducts, if other associated structural properties of Et 743-DNA adducts are taken into account. In particular, the wedge-shaped Et 743, which forces open the minor groove of DNA, introducing a major groove bend, and the extrahelical protrusion of the C-subunit of Et 743 provide unique characteristics alongside the hydrogen-bonding stabilization of a covalent DNA adduct, which we propose traps an intermediate in NER processing of Et 743-DNA adducts. This trapped intermediate protein-Et 743-DNA adduct complex can be considered analogous to a poisoned topoisomerase I- or topoisomerase II-DNA complex. In the absence of an intact NER nuclease complex, this toxic lesion is unable to form, and the Et 743-DNA adducts, although not repaired by the NER pathway, are less toxic to cells. Conversely, elevated levels of either of these nucleases should lead to enhanced Et 743 toxicity.
BACKGROUND: Ecteinascidin 743 (Et 743) is a potent antitumor marine alkaloid currently undergoing phase II clinical trials. The synthetic analog phthalascidin (Pt 650), a designed structural analog of Et 743 displays in vitro potency comparable to Et 743. In this study, we used a panel of 36 human cancer cell lines, flow cytometry and oligonucleotide microarrays to analyze further these two compounds in a parallel fashion with regard to both antitumor activity (phenotype) and gene expression (genotype) bases. RESULTS: The cancer panel experiment established that activity patterns of Et 743 and Pt 650 were essentially the same with their IC(50) values ranging from pM to low nM. By means of flow cytometric cell cycle analysis using HCT116 cells, they were shown to disrupt S phase progression after a 12-h treatment at 2.0 nM, eventually resulting in the late S and G2/M accumulation at the 24-h time point. Array-based gene expression monitoring also demonstrated that the Et 743 and Pt 650 profiles were highly similar in two distinct cancer cell lines, HCT116 colon and MDA-MB-435 breast. Characteristic changes were observed in subsets of genes involved in DNA damage response, transcription and signal transduction. In HCT116 carrying the wild-type p53 tumor suppressor gene, the up-regulation of several p53-responsive genes was evident. Furthermore, a subset of genes encoding DNA-binding proteins to specific promoter regions (e.g. the CCAAT box) was down-regulated in both cell lines, suggesting one potential mode of action of this series of antitumor agents. CONCLUSION: A combination of gene expression analysis using oligonucleotide microarrays and flow cytometry confirms an earlier finding that Et 743 and Pt 650 have remarkably similar biological activities.
Saframycin A (SafA) is a natural product that inhibits human cancer cell proliferation. Its synthetic analog, QAD, is a more potent inhibitor of these cells. SafA does not affect wild-type yeast, but it does inhibit growth of the strain CCY333 (DeltaPDR1/PDR3/ERG6) (IC50 = 0.9 microM). QAD is also a more effective inhibitor of CCY333 growth (IC50 = 0.4 microM). Transcription profiling of SafA- and QAD-treated CCY333 cultures showed that both drugs generated nearly identical profiles, with altered expression levels (> or =2-fold) of more than 240 genes. Both agents induced the overexpression of genes involved in glycolysis, oxidative stress, and protein degradation and repressed genes encoding histones, biosynthetic enzymes, and the cellular import machinery. Significantly, neither drug affected the expression of known DNA-damage repair genes, as might have been expected if their primary mechanism of action involved the covalent modification of DNA.