High-grade serous ovarian cancer (HGSOC) accounts for 70-80% of ovarian cancer deaths, and overall survival has not changed significantly for several decades. In this Opinion article, we outline a set of research priorities that we believe will reduce incidence and improve outcomes for women with this disease. This ‘roadmap’ for HGSOC was determined after extensive discussions at an Ovarian Cancer Action meeting in January 2015.
The 5’terminal oligopyrimidine (5’TOP) motif is a cis-regulatory RNA element located immediately downstream of the 7-methylguanosine [m7G] cap of TOP mRNAs, which encode ribosomal proteins and translation factors. In eukaryotes, this motif coordinates the synchronous and stoichiometric expression of the protein components of the translation machinery. La-related protein 1 (LARP1) binds TOP mRNAs, regulating their stability and translation. We present crystal structures of the human LARP1 DM15 region in complex with a 5’TOP motif, a cap analog (m7GTP), and a capped cytidine (m7GpppC), resolved to 2.6, 1.8 and 1.7 Å, respectively. Our binding, competition, and immunoprecipitation data corroborate and elaborate on the mechanism of 5’TOP motif binding by LARP1. We show that LARP1 directly binds the cap and adjacent 5’TOP motif of TOP mRNAs, effectively impeding access of eIF4E to the cap and preventing eIF4F assembly. Thus, LARP1 is a specialized TOP mRNA cap-binding protein that controls ribosome biogenesis.DOI: http://dx.doi.org/10.7554/eLife.24146.001
Gemcitabine is a nucleoside analogue commonly used in cancer therapy but with limited efficacy due to a high susceptibility to cancer cell resistance. The addition of a phosphoramidate motif to the gemcitabine can protect it against many of the key cancer resistance mechanisms. We have synthesized a series of gemcitabine phosphoramidate prodrugs and screened for cytostatic activity in a range of different tumor cell lines. Among the synthesized compounds, one in particular (NUC-1031, 6f) was shown to be potent in vitro. Importantly, compared with gemcitabine, 6f activation was significantly less dependent on deoxycytidine kinase and on nucleoside transporters, and it was resistant to cytidine deaminase-mediated degradation. Moreover, 6f showed a significant reduction in tumor volumes in vivo in pancreatic cancer xenografts. The ProTide 6f is now in clinical development with encouraging efficacy signals in a Phase I/II study, which strongly supports the ProTide approach to generate promising new anticancer agents.
RNA-binding proteins (RBPs) bind to and post-transcriptionally regulate the stability of mRNAs. La-related protein 1 (LARP1) is a conserved RBP that interacts with poly-A-binding protein and is known to regulate 5′-terminal oligopyrimidine tract (TOP) mRNA translation. Here, we show that LARP1 is complexed to 3000 mRNAs enriched for cancer pathways. A prominent member of the LARP1 interactome is mTOR whose mRNA transcript is stabilized by LARP1. At a functional level, we show that LARP1 promotes cell migration, invasion, anchorage-independent growth and in vivo tumorigenesis. Furthermore, we show that LARP1 expression is elevated in epithelial cancers such as cervical and non-small cell lung cancers, where its expression correlates with disease progression and adverse prognosis, respectively. We therefore conclude that, through the post-transcriptional regulation of genes such as mTOR within cancer pathways, LARP1 contributes to cancer progression.
SummaryBackgroundCarboplatin and paclitaxel administered every 3 weeks is standard-of-care first-line chemotherapy for epithelial ovarian cancer. The Japanese JGOG3016 trial showed a significant improvement in progression-free and overall survival with dose-dense weekly paclitaxel and 3-weekly carboplatin. In this study, we aimed to compare efficacy and safety of two dose-dense weekly regimens to standard 3-weekly chemotherapy in a predominantly European population with epithelial ovarian cancer.MethodsIn this phase 3 trial, women with newly diagnosed International Federation of Gynecology and Obstetrics stage IC–IV epithelial ovarian cancer were randomly assigned to group 1 (carboplatin area under the curve [AUC]5 or AUC6 and 175 mg/m2 paclitaxel every 3 weeks), group 2 (carboplatin AUC5 or AUC6 every 3 weeks and 80 mg/m2 paclitaxel weekly), or group 3 (carboplatin AUC2 and 80 mg/m2 paclitaxel weekly). Written informed consent was provided by all women who entered the trial. The protocol had the appropriate national research ethics committee approval for the countries where the study was conducted. Patients entered the trial after immediate primary surgery, or before neoadjuvant chemotherapy with subsequent planned delayed primary surgery. The trial coprimary outcomes were progression-free survival and overall survival. Data analyses were done on an intention-to-treat basis, and were powered to detect a hazard ratio of 0·75 in progression-free survival. The main comparisons were between the control group (group 1) and each of the weekly research groups (groups 2 and 3).FindingsBetween June 6, 2011, and Nov 28, 2014, 1566 women were randomly assigned to treatment. 72% (365), completed six protocol-defined treatment cycles in group 1, 60% (305) in group 2, and 63% (322) in group 3, although 90% (454), 89% (454), and 85% (437) completed six platinum-based chemotherapy cycles, respectively. Paclitaxel dose intensification was achieved with weekly treatment (median total paclitaxel dose 1010 mg/m2 in group 1; 1233 mg/m2 in group 2; 1274 mg/m2 in group 3). By February, 2017, 1018 (65%) patients had experienced disease progression. No significant progression-free survival increase was observed with either weekly regimen (restricted mean survival time 24·4 months [97·5% CI 23·0–26·0] in group 1, 24·9 months [24·0–25·9] in group 2, 25·3 months [23·9–26·9] in group 3; median progression-free survival 17·7 months [IQR 10·6–not reached] in group 1, 20·8 months [11·9–59·0] in group 2, 21·0 months [12·0–54·0] in group 3; log-rank p=0·35 for group 2 vs group 1; group 3 vs 1 p=0·51). Although grade 3 or 4 toxic effects increased with weekly treatment, these effects were predominantly uncomplicated. Febrile neutropenia and sensory neuropathy incidences were similar across groups.InterpretationWeekly dose-dense chemotherapy can be delivered successfully as first-line treatment for epithelial ovarian cancer but does not significantly improve progression-free survival compared with standard 3-weekly chemotherapy in predominantly Eur...
Oncologists traditionally assess their patients' ECOG performance status (PS), and few studies have evaluated the accuracy of these assessments. In this study, 101 patients attending a rapid access clinic at Papworth Hospital with a diagnosis of lung cancer were asked to assess their own ECOG PS score on a scale between 0 and 4. Patients' scores were compared to the PS assessment of them made by their oncologists. Of 98 patients with primary non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC), weighted k statistics showed PS score agreement between patient and oncologist of 0.45. Both patient-and oncologist-assessed scores reflected survival duration (in NSCLC and SCLC) as well as disease stage (in NSCLC), with oncologist-assessed scores being only marginally more predictive of survival. There was no sex difference in patient assessment of PS scores, but oncologists scored female patients more pessimistically than males. This study showed that, with few exceptions, patients and oncologists assessed PS scores similarly. Although oncologists should continue to score PS objectively, it may benefit their clinical practice to involve their patients in these assessments. Performance statusDavid A Karnofsky and colleagues described the first performance status (PS) score in 1948 (Karnofsky et al, 1948). It was introduced for assessing patients receiving nitrogen mustard chemotherapy for primary lung carcinoma. Each patient was given a score on a linear scale between 0 (dead) and 100 (normally active), summarising their ability to perform daily activities, and the level of assistance they required in order to do so. This scoring system was subsequently used throughout oncology practice as a numerical guide to patients' general health. In 1960, the Eastern Co-operative Oncology Group (ECOG) introduced a simpler 'ECOG performance status' scale, similar to the Karnofsky PS (KPS) scale, with only five points. This is now termed the ECOG/ WHO score (Oken et al, 1982) having been expanded to comprise of six points with the addition of PS 5 (Figure 1).In a Medline Search using the terms 'clinical trial and Karnofsky/WHO or ECOG performance status', 233 and 84 authors used the ECOG and Karnofsky scores, respectively. Generally, the two scores have been proven to be interchangeable (Taylor et al, 1999), although the ECOG is often preferred for its simplicity. Interobserver agreementA score is reliable if there is good concordance between observers, and low rates of inter-and intraobserver variability. Studies of this have been conflicting. When health professionals were asked to assess the KPS of 75 cancer patients, Yates et al (1980) found moderate agreement (correlation coefficient 0.69) between nurses and social workers. Oncologists and psychiatrists or psychologists had greater agreement with a correlation coefficient of 0.79. Roila et al (1991) showed very high interobserver correlation between two oncologists in assessing both the Karnofsky (coefficient 0.92) and ECOG (coefficient 0.91) scores in 209 canc...
Protein synthesis is a tightly regulated process that enables post-transcriptional control of gene expression. Dysregulation of this process is associated with the development and progression of cancers because components of the translational machinery function at the point of convergence of aberrant cell signaling pathways. Drugs designed to inhibit mRNA translation are currently in preclinical and early clinical development, and are likely to provide effective anticancer strategies in the future. In this Review, we summarize the main components of translation and describe how alterations in these proteins and their principle upstream signaling pathways can impact on cancer. The first inhibitors of translation, drugs designed to target eIF4E, have been trialed in hematologic malignancies, while antisense oligonucleotides against eIF4E are also due to enter clinical trials. Here, we discuss the mode of action of drugs designed to inhibit mRNA translation and other promising therapies that are in preclinical development with the aim of becoming anticancer agents.
RNA-binding proteins (RBPs) are increasingly identified as post-transcriptional drivers of cancer progression. The RBP LARP1 is an mRNA stability regulator, and elevated expression of the protein in hepatocellular and lung cancers is correlated with adverse prognosis. LARP1 associates with an mRNA interactome that is enriched for oncogenic transcripts. Here we explore the role of LARP1 in epithelial ovarian cancer, a disease characterized by the rapid acquisition of resistance to chemotherapy through the induction of pro-survival signalling. We show, using ovarian cell lines and xenografts, that LARP1 is required for cancer cell survival and chemotherapy resistance. LARP1 promotes tumour formation in vivo and maintains cancer stem cell-like populations. Using transcriptomic analysis following LARP1 knockdown, cross-referenced against the LARP1 interactome, we identify BCL2 and BIK as LARP1 mRNA targets. We demonstrate that, through an interaction with the 3′ untranslated regions (3′ UTRs) of BCL2 and BIK, LARP1 stabilizes BCL2 but destabilizes BIK with the net effect of resisting apoptosis. Together, our data indicate that by differentially regulating the stability of a selection of mRNAs, LARP1 promotes ovarian cancer progression and chemotherapy resistance.
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