Explore the vast range of titles available.

Current KRAS G12C (OFF) inhibitors that target inactive GDP-bound KRAS G12C cause responses in less than half of patients and these responses are not durable. A class of RAS G12C (ON) inhibitors that targets active GTP-bound KRAS G12C blocks ERK signaling more potently than the inactive-state inhibitors. Sensitivity to either class of agents is strongly correlated with inhibition of mTORC1 activity. We have previously shown that PI3K/mTOR and ERK-signaling pathways converge on key cellular processes and that inhibition of both pathways is required for inhibition of these processes and for significant antitumor activity. We find here that the combination of a KRAS G12C inhibitor with a selective mTORC1 kinase inhibitor causes synergistic inhibition of Cyclin D1 expression and cap-dependent translation. Moreover, BIM upregulation by KRAS G12C inhibition and inhibition of MCL-1 expression by the mTORC1 inhibitor are both required to induce significant cell death. In vivo, this combination causes deep, durable tumor regressions and is well tolerated. This study suggests that the ERK and PI3K/mTOR pathways each mitigate the effects of inhibition of the other and that combinatorial inhibition is a potential strategy for treating KRAS G12C -dependent lung cancer. Despite the development of inhibitors targeting active GTP-bound (ON) KRAS(G12C) for the treatment of KRAS G12C-driven non-small cell lung cancer (NSCLC), resistance remains an issue. Here, the authors show that despite inhibition of KRAS G12C ON, there is residual mTOR activity driving resistance, which was successfully targeted by combining with a selective mTOR inhibitor.

The majority of human breast cancers are dependent on hormone-stimulated estrogen receptor alpha (ER) and are sensitive to its inhibition. Treatment resistance arises in most advanced cancers due to genetic alterations that promote ligand independent activation of ER itself or ER target genes. Whereas re-targeting of the ER ligand binding domain (LBD) with newer ER antagonists can work in some cases, these drugs are largely ineffective in many genetic backgrounds including ER fusions that lose the LBD or in cancers that hyperactivate ER targets. By identifying the mechanism of ER translation, we herein present an alternative strategy to target ER and difficult to treat ER variants. We find that ER translation is cap-independent and mTOR inhibitor insensitive, but dependent on 5' UTR elements and sensitive to pharmacologic inhibition of the translation initiation factor eIF4A, an mRNA helicase. EIF4A inhibition rapidly reduces expression of ER and short-lived targets of ER such as cyclin D1 and other components of the cyclin D-CDK complex in breast cancer cells. These effects translate into suppression of growth of a variety of ligand-independent breast cancer models including those driven by ER fusion proteins that lack the ligand binding site. The efficacy of eIF4A inhibition is enhanced when it is combined with fulvestrant-an ER degrader. Concomitant inhibition of ER synthesis and induction of its degradation causes synergistic and durable inhibition of ER expression and tumor growth. The clinical importance of these findings is confirmed by results of an early clinical trial (NCT04092673) of the selective eIF4A inhibitor zotatifin in patients with estrogen receptor positive metastatic breast cancer. Multiple clinical responses have been observed on combination therapy including durable regressions. These data suggest that eIF4A inhibition could be a useful new strategy for treating advanced ER+ breast cancer.

In space mission architectures, redundancy of subsystems mitigates the risk of isolated malfunctions, but not the risk of the entire platform being targeted by hostile forces. This dissertation explores the use of deception as a tactical defense mechanism. The scenario of a satellite accomplishing an unknown mission while evading a dedicated ground sensor is modeled as a two-player zero-sum game, which supports a robust performance assessment based on both the satellite and the sensor optimizing against each other. Moreover, the methodology determines the optimal strategies and associated performance based on assumed constraints that can be varied parametrically, so the method can be adapted to a range of specific scenarios as well as to advances in underlying technologies. The two player game, which featured infinite strategy choices for both players, was solved using a reinforcement learning/neural network approach, specifically proximal policy optimization, capable of high-fidelity strategy tuning. Parametric sensitivity analysis on the results, computationally impractical with proximal policy optimization, was instead accomplished with coevolution, a genetic algorithm approach. The primary result is that, under reasonable technological assumptions for both players, an evading spacecraft can expect to avoid detection by an optimally tracking optical sensor just under 60% of the time, and can accomplish this evasion expending, on average, just under 16 m/s of ΔV every 5 days. Analysis also indicated that this result is more sensitive to the sensor’s parameters than the satellite’s. Additional results compare the computational methodologies employed. The impact of the research as a methodological innovation is discussed and future direction is offered for applying the methodology to other problems, as well as possible refinements in the context of this application.

Current KRAS (OFF) inhibitors that target inactive GDP-bound KRAS cause responses in less than half of patients and these responses are not durable. A class of RAS (ON) inhibitors that targets active GTP-bound KRAS blocks ERK signaling more potently than the inactive-state inhibitors. Sensitivity to either class of agents is strongly correlated with inhibition of mTORC1 activity. We have previously shown that PI3K/mTOR and ERK-signaling pathways converge on key cellular processes and that inhibition of both pathways is required for inhibition of these processes and for significant antitumor activity. We find here that the combination of a KRAS inhibitor with a selective mTORC1 kinase inhibitor causes synergistic inhibition of Cyclin D1 expression and cap-dependent translation. Moreover, BIM upregulation by KRAS inhibition and inhibition of MCL-1 expression by the mTORC1 inhibitor are both required to induce significant cell death. In vivo, this combination causes deep, durable tumor regressions and is well tolerated. This study suggests that the ERK and PI3K/mTOR pathways each mitigate the effects of inhibition of the other and that combinatorial inhibition is a potential strategy for treating KRAS -dependent lung cancer.

In the 1980s, DNA-based molecular markers were identified as having the potential to enhance corn (Zea mays L.) breeding. Research has demonstrated the advantage of using molecular markers for selection of simply inherited traits, however only a few studies have evaluated the potential to enhance genetic gain for quantitative traits. In the late 1990s, Monsanto decided to implement marker assisted selection for quantitative traits in our global plant breeding programs. We built genotyping systems and information tools and developed marker assisted methodologies that increased the mean performance in elite breeding populations.

Randomised trials have investigated various androgen deprivation therapy (ADT) intensification strategies in men receiving radiotherapy for the treatment of prostate cancer. This individual patient data meta-analysis of relevant randomised trials aimed to quantify the benefit of these interventions in aggregate and in clinically relevant subgroups. For this meta-analysis, we performed a systematic literature search in MEDLINE, Embase, trial registries, the Web of Science, Scopus, and conference proceedings to identify trials with results published in English between Jan 1, 1962, and Dec 30, 2020. Multicentre randomised trials were eligible if they evaluated the use or prolongation of ADT (or both) in men with localised prostate cancer receiving definitive radiotherapy, reported or collected distant metastasis and survival data, and used ADT for a protocol-defined finite duration. The Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) Consortium was accessed to obtain individual patient data from randomised trials. The primary outcome was metastasis-free survival. Hazard ratios (HRs) were obtained through stratified Cox models for ADT use (radiotherapy alone vs radiotherapy plus ADT), neoadjuvant ADT extension (ie, extension of total ADT duration in the neoadjuvant setting from 3–4 months to 6–9 months), and adjuvant ADT prolongation (ie, prolongation of total ADT duration in the adjuvant setting from 4–6 months to 18–36 months). Formal interaction tests between interventions and metastasis-free survival were done for prespecified subgroups defined by age, National Comprehensive Cancer Network (NCCN) risk group, and radiotherapy dose. This meta-analysis is registered with PROSPERO, CRD42021236855. Our search returned 12 eligible trials that provided individual patient data (10 853 patients) with a median follow-up of 11·4 years (IQR 9·0–15·0). The addition of ADT to radiotherapy significantly improved metastasis-free survival (HR 0·83 [95% CI 0·77–0·89], p<0·0001), as did adjuvant ADT prolongation (0·84 [0·78–0·91], p<0·0001), but neoadjuvant ADT extension did not (0·95 [0·83–1·09], p=0·50). Treatment effects were similar irrespective of radiotherapy dose, patient age, or NCCN risk group. Our findings provide the strongest level of evidence so far to the magnitude of the benefit of ADT treatment intensification with radiotherapy for men with localised prostate cancer. Adding ADT and prolonging the portion of ADT that follows radiotherapy is associated with improved metastasis-free survival in men, regardless of risk group, age, and radiotherapy dose delivered; however, the magnitude of the benefit could vary and shared decision making with patients is recommended. University Hospitals Seidman Cancer Center, Prostate Cancer Foundation, and the American Society for Radiation Oncology.

Due to volatile sugar prices, the food vs fuel debate, and recent increases in the supply of natural gas, methanol has emerged as a promising feedstock for the bio-based economy. However, attempts to engineer Escherichia coli to metabolize methanol have achieved limited success. Here, we provide a rigorous systematic analysis of several potential pathway bottlenecks. We show that regeneration of ribulose 5-phosphate in E. coli is insufficient to sustain methanol assimilation, and overcome this by activating the sedoheptulose bisphosphatase variant of the ribulose monophosphate pathway. By leveraging the kinetic isotope effect associated with deuterated methanol as a chemical probe, we further demonstrate that under these conditions overall pathway flux is kinetically limited by methanol dehydrogenase. Finally, we identify NADH as a potent kinetic inhibitor of this enzyme. These results provide direction for future engineering strategies to improve methanol utilization, and underscore the value of chemical biology methodologies in metabolic engineering. Engineering E. coli for metabolization of methanol to produce fuels and chemicals has not been fully achieved. Here, the authors combine metabolic engineering and chemical inhibition to improve methanol assimilation and distinguish the role of kinetics and thermodynamics under various culture conditions.

The telomere repeat-containing RNA (TERRA) forms R-loops to promote homology-directed DNA synthesis in the alternative lengthening of telomere (ALT) pathway. Here we report that TERRA contributes to ALT via interacting with the lysine-specific demethylase 1A (LSD1 or KDM1A). We show that LSD1 localizes to ALT telomeres in a TERRA dependent manner and LSD1 function in ALT is largely independent of its demethylase activity. Instead, LSD1 promotes TERRA recruitment to ALT telomeres via RNA binding. In addition, LSD1 and TERRA undergo phase separation, driven by interactions between the RNA binding properties of LSD1 and the G-quadruplex structure of TERRA. Importantly, the formation of TERRA-LSD1 condensates enriches the R-loop stimulating protein Rad51AP1 and increases TERRA-containing R-loops at telomeres. Our findings suggest that LSD1-TERRA phase separation enhances the function of R-loop regulatory molecules for ALT telomere maintenance, providing a mechanism for how the biophysical properties of histone modification enzyme-RNA interactions impact chromatin function. Here the authors show that the telomere repeat-containing RNA (TERRA) undergoes phase separation with the lysine-specific demethylase 1A (LSD1) to promote R-loop formation for homology-directed telomere DNA synthesis in the alternative lengthening of telomere (ALT) pathway.

The origin and functions of mast cells (MCs) have been debated since their description by Paul Ehrlich in 1879. MCs have long been considered 'reactive bystanders' and 'amplifiers' in inflammatory processes, allergic reactions, and host responses to infectious diseases. However, knowledge about the origin, phenotypes and functions of MCs has increased substantially over the past 50 years. MCs are now known to be derived from multipotent hematopoietic progenitors, which, through a process of differentiation and maturation, form a unique hematopoietic lineage residing in multiple organs. In particular, MCs are distinguishable from basophils and other hematopoietic cells by their unique phenotype, origin(s), and spectrum of functions, both in innate and adaptive immune responses and in other settings. The concept of a unique MC lineage is further supported by the development of a distinct group of neoplasms, collectively referred to as mastocytosis, in which MC precursors expand as clonal cells. The clinical consequences of the expansion and/or activation of MCs are best established in mastocytosis and in allergic inflammation. However, MCs have also been implicated as important participants in a number of additional pathologic conditions and physiological processes. In this article, we review concepts regarding MC development, factors controlling MC expansion and activation, and some of the fundamental roles MCs may play in both health and disease. We also discuss new concepts for suppressing MC expansion and/or activation using molecularly-targeted drugs.

Midostaurin is a multikinase inhibitor that includes mutant and nonmutant KIT D816V as a target. Its use in patients with advanced systemic mastocytosis, including mast-cell leukemia, produced responses in 60%, with a median overall survival of 28.7 months. Systemic mastocytosis is a myeloid neoplasm that is caused by the accumulation of abnormal mast cells in the bone marrow, liver, spleen, and skin. 1 The KIT D816V mutation, which is detected in approximately 90% of patients, encodes a constitutively activated receptor tyrosine kinase that drives disease pathogenesis. 2 , 3 The World Health Organization (WHO) classification of advanced systemic mastocytosis includes aggressive systemic mastocytosis, systemic mastocytosis with an associated hematologic neoplasm (also termed systemic mastocytosis with an associated hematologic non–mast-cell-lineage disease), and mast-cell leukemia (Table S1 in the Supplementary Appendix, available with the full text of this article at NEJM.org). 4 Symptoms are caused . . .