Concurrent inhibition of oncogenic and wild-type RAS-GTP for cancer therapy.

RAS oncogenes (collectively NRAS, HRAS and especially KRAS) are among the most frequently mutated genes in cancer, with common driver mutations occurring at codons 12, 13 and 611. Small molecule inhibitors of the KRAS(G12C) oncoprotein have demonstrated clinical efficacy in patients with multiple cancer types and have led to regulatory approvals for the treatment of non-small cell lung cancer2,3. Nevertheless, KRASG12C mutations account for only around 15% of KRAS-mutated cancers4,5, and there are no approved KRAS inhibitors for the majority of patients with tumours containing other common KRAS mutations. Here we describe RMC-7977, a reversible, tri-complex RAS inhibitor with broad-spectrum activity for the active state of both mutant and wild-type KRAS, NRAS and HRAS variants (a RAS(ON) multi-selective inhibitor). Preclinically, RMC-7977 demonstrated potent activity against RAS-addicted tumours carrying various RAS genotypes, particularly against cancer models with KRAS codon 12 mutations (KRASG12X). Treatment with RMC-7977 led to tumour regression and was well tolerated in diverse RAS-addicted preclinical cancer models. Additionally, RMC-7977 inhibited the growth of KRASG12C cancer models that are resistant to KRAS(G12C) inhibitors owing to restoration of RAS pathway signalling. Thus, RAS(ON) multi-selective inhibitors can target multiple oncogenic and wild-type RAS isoforms and have the potential to treat a wide range of RAS-addicted cancers with high unmet clinical need. A related RAS(ON) multi-selective inhibitor, RMC-6236, is currently under clinical evaluation in patients with KRAS-mutant solid tumours (ClinicalTrials.gov identifier: NCT05379985).

Stereoselective Synthesis of Either Exo- or Endo-3-Azabicyclo[3.1.0]hexane-6-carboxylates by Dirhodium(II)-Catalyzed Cyclopropanation with Ethyl Diazoacetate under Low Catalyst Loadings.

Although cyclopropanation with donor/acceptor carbenes can be conducted under low catalyst loadings (<0.001 mol %), such low loading has not been generally effective for other classes of carbenes such as acceptor carbenes. In this current study, we demonstrate that ethyl diazoacetate can be effectively used in the cyclopropanation of N-Boc-2,5-dihydropyrrole with dirhodium(II) catalyst loadings of 0.005 mol %. By appropriate choice of catalyst and hydrolysis conditions, either the exo- or endo-3-azabicyclo[3.1.0]hexanes can be formed cleanly with high levels of diastereoselectivity with no chromatographic purification.

Chemical remodeling of a cellular chaperone to target the active state of mutant KRAS.

The discovery of small-molecule inhibitors requires suitable binding pockets on protein surfaces. Proteins that lack this feature are considered undruggable and require innovative strategies for therapeutic targeting. KRAS is the most frequently activated oncogene in cancer, and the active state of mutant KRAS is such a recalcitrant target. We designed a natural product-inspired small molecule that remodels the surface of cyclophilin A (CYPA) to create a neomorphic interface with high affinity and selectivity for the active state of KRASG12C (in which glycine-12 is mutated to cysteine). The resulting CYPA:drug:KRASG12C tricomplex inactivated oncogenic signaling and led to tumor regressions in multiple human cancer models. This inhibitory strategy can be used to target additional KRAS mutants and other undruggable cancer drivers. Tricomplex inhibitors that selectively target active KRASG12C or multiple RAS mutants are in clinical trials now (NCT05462717 and NCT05379985).

RAS-dependent RAF-MAPK hyperactivation by pathogenic RIT1 is a therapeutic target in Noonan syndrome-associated cardiac hypertrophy.

RIT1 is a RAS guanosine triphosphatase (GTPase) that regulates different aspects of signal transduction and is mutated in lung cancer, leukemia, and in the germline of individuals with Noonan syndrome. Pathogenic RIT1 proteins promote mitogen-activated protein kinase (MAPK) hyperactivation; however, this mechanism remains poorly understood. Here, we show that RAF kinases are direct effectors of membrane-bound mutant RIT1 necessary for MAPK activation. We identify critical residues in RIT1 that facilitate interaction with membrane lipids and show that these are necessary for association with RAF kinases and MAPK activation. Although mutant RIT1 binds to RAF kinases directly, it fails to activate MAPK signaling in the absence of classical RAS proteins. Consistent with aberrant RAF/MAPK activation as a driver of disease, we show that pathway inhibition alleviates cardiac hypertrophy in a mouse model of RIT1 mutant Noonan syndrome. These data shed light on the function of pathogenic RIT1 and identify avenues for therapeutic intervention.

Pan-KRAS inhibitor disables oncogenic signalling and tumour growth.

KRAS is one of the most commonly mutated proteins in cancer, and efforts to directly inhibit its function have been continuing for decades. The most successful of these has been the development of covalent allele-specific inhibitors that trap KRAS G12C in its inactive conformation and suppress tumour growth in patients1-7. Whether inactive-state selective inhibition can be used to therapeutically target non-G12C KRAS mutants remains under investigation. Here we report the discovery and characterization of a non-covalent inhibitor that binds preferentially and with high affinity to the inactive state of KRAS while sparing NRAS and HRAS. Although limited to only a few amino acids, the evolutionary divergence in the GTPase domain of RAS isoforms was sufficient to impart orthosteric and allosteric constraints for KRAS selectivity. The inhibitor blocked nucleotide exchange to prevent the activation of wild-type KRAS and a broad range of KRAS mutants, including G12A/C/D/F/V/S, G13C/D, V14I, L19F, Q22K, D33E, Q61H, K117N and A146V/T. Inhibition of downstream signalling and proliferation was restricted to cancer cells harbouring mutant KRAS, and drug treatment suppressed KRAS mutant tumour growth in mice, without having a detrimental effect on animal weight. Our study suggests that most KRAS oncoproteins cycle between an active state and an inactive state in cancer cells and are dependent on nucleotide exchange for activation. Pan-KRAS inhibitors, such as the one described here, have broad therapeutic implications and merit clinical investigation in patients with KRAS-driven cancers.

Corrigendum: Digitalization and digital transformation in higher education: A bibliometric analysis.

[This corrects the article DOI: 10.3389/fpsyg.2022.1081595.].

Blood component requirements in liver transplantation: effect of 2 thromboelastometry-guided strategies for bolus fibrinogen infusion-the TROMBOFIB randomized trial.

BACKGROUND: A low plasma fibrinogen level influences blood component transfusion. Thromboelastometry provides clinical guidance for fibrinogen replacement in liver transplantation (LT). OBJECTIVES: We hypothesized that infusions of fibrinogen concentrate to reach an A10FibTem value of 11 mm during LT could reduce red blood cell (RBC) and other component and fluid requirements in comparison to standard care. METHODS: This randomized, blinded, multicenter trial in 3 hospitals enrolled 189 LT-scheduled patients allocated to an intervention target (A10FibTem, 11 mm) or a standard target (A10FibTem, 8 mm); 176 patients underwent LT with fibrinogen replacement. Data were analyzed by intention-to-treat (intervention group, 91; control group, 85). Blood was extracted, and fibrinogen kits were prepared to bring each patient's fibrinogen level to the assigned target at the start of LT, after portal vein clamping, and after graft reperfusion. The main outcome was the proportion of patients requiring RBC transfusion during LT or within 24 hours. RESULTS: The proportion of patients requiring RBCs did not differ between the groups: intervention, 74.7% (95% CI, 65.5%-83.3%); control, 72.9% (95% CI, 62.2%-82.0%); absolute difference, 1.8% (95% CI, -11.1% to 14.78%) (P = .922). Thrombotic events occurred in 4% of the patients in both groups; reoperation and retransplantation rates and mortality did not differ. Nearly 70% of the patients in both groups required fibrinogen concentrate to reach the target. Using an 11-mm A10FibTem target increased the maximum clot firmness without affecting safety. However, this change provided no clinical benefits. CONCLUSION: The similar low plasma fibrinogen concentrations could explain the lack of significant between-group outcomes.

Digitalization and digital transformation in higher education: A bibliometric analysis.

The new paradigms that are emerging because of technological and social advances derived from the massive use of information and communication technologies (ICTs) are generating a transformative process that is modifying all economic sectors, and education is no exception. Higher Education Institutions (HEIs) are carrying out such transformation, reacting to the need of adaptation to this new reality, experiencing a complete cultural change that is challenging the attitudes, actions and values shared by the members and stakeholders of these organizations. In order to analyze the scientific literature about this topic, a bibliometric analysis has been carried out covering the period 1900-2021, considering a sample of 469 articles included in the Web of Science (WoS) database. The results show the multidisciplinary nature of the topic, including articles published in different areas, as well as its close link with aspects such as innovation, governance and agile methodologies. Finally, this study highlights the main lines of research that could attract more attention in the immediate future.

Impaired Proteolysis of Noncanonical RAS Proteins Drives Clonal Hematopoietic Transformation.

Recently, screens for mediators of resistance to FLT3 and ABL kinase inhibitors in leukemia resulted in the discovery of LZTR1 as an adapter of a Cullin-3 RING E3 ubiquitin ligase complex responsible for the degradation of RAS GTPases. In parallel, dysregulated LZTR1 expression via aberrant splicing and mutations was identified in clonal hematopoietic conditions. Here we identify that loss of LZTR1, or leukemia-associated mutants in the LZTR1 substrate and RAS GTPase RIT1 that escape degradation, drives hematopoietic stem cell (HSC) expansion and leukemia in vivo. Although RIT1 stabilization was sufficient to drive hematopoietic transformation, transformation mediated by LZTR1 loss required MRAS. Proteolysis targeting chimeras (PROTAC) against RAS or reduction of GTP-loaded RAS overcomes LZTR1 loss-mediated resistance to FLT3 inhibitors. These data reveal proteolysis of noncanonical RAS proteins as novel regulators of HSC self-renewal, define the function of RIT1 and LZTR1 mutations in leukemia, and identify means to overcome drug resistance due to LZTR1 downregulation. SIGNIFICANCE: Here we identify that impairing proteolysis of the noncanonical RAS GTPases RIT1 and MRAS via LZTR1 downregulation or leukemia-associated mutations stabilizing RIT1 enhances MAP kinase activation and drives leukemogenesis. Reducing the abundance of GTP-bound KRAS and NRAS overcomes the resistance to FLT3 kinase inhibitors associated with LZTR1 downregulation in leukemia. This article is highlighted in the In This Issue feature, p. 2221.

Short-term Neuropsychiatric and Body Weight Changes in Patients Switching From EVG/Cobi/FTC/TAF to BIC/FTC/TAF (PreEC/RIS69).

BACKGROUND: We report NP, clinical and laboratory changes in patients switching from EVG/Cobi/FTC/TAF to BIC/FTC/TAF in clinical practice. METHODS: A group of subjects switching from EVG/Cobi/FTC/TAF to BIC/F/TAF was prospectively followed. A validated sleep quality questionnaire (Pittsburgh Sleep Quality Index), as well as the Hospital Anxiety and Depression Scale (HADS), were administered after 4 weeks from the treatment switch. Adverse events, side effects and discontinuation were recorded at weeks 4 and 24. Pretreatment switch and week 24 body weight and laboratory data were compared. RESULTS: A total of 96 virologically suppressed patients (86% male) were included. All patients received EVG/Cobi/FTC/TAF at least 1 year before the treatment switch. Median (IQR) nadir CD4 was 367 (263). The most common comorbidities were dyslipidemia, HTA and diabetes, 26%, 14% and 7%, respectively. Depression was reported by 8%. Five patients discontinued BIC/FTC/TAF before week 4 due to intolerance (2 insomnia, 1 headache and 2 GI symptoms). No changes in sleep quality, anxiety and depression outcomes were observed at week 4 (p = 0.1, p = 0.1 and p = 0.3, respectively). After 6 months, the median body weight change was statistically significant (0.6 kg, p = 0.003). All patients maintained HIV suppression. CONCLUSION: Except in a few cases, sleep quality, anxiety and depression symptoms remain stable in HIV virologically suppressed patients on EVG/Cobi/FTC/TAF who switch to BIC/F/TAF. NPAEs are mild and tend to occur in those with previous neuropsychiatric symptoms. Weight gain tends to be small but statistically significant. Long-term follow-up in "real-life" cohorts would be needed to confirm these findings.

Estimation of Ecological and Human Health Risks Posed by Heavy Metals in Street Dust of Madrid City (Spain).

In this work, sampling was carried out in the urban area of Madrid to analyze the content of total heavy metals (Zn, Pb, Cu, Cr, Ni, and Cd) in the street dust. Contamination was evaluated using various indices, such as the Contamination Factor (CF), Enrichment Factor (EF), Geo-accumulation Index (Igeo), Potential Ecological Risk Index (RI), Pollution Load Index (PLI), the Human Health Index Hazard Index (HI), and Cancer Risk (CR). Pollution indices were related to traffic density and color. Traffic density was the factor that most influenced the values of the pollution indexes, but no significant differences were found with the color of street dust. The concentration of heavy metals in the urban dust of Madrid had the following sequence: Zn (895) > Cu (411) > Pb (290) > Cr (100) > Ni (42) > Cd (1.25 mg kg−1). The pollution levels were high or very high in Pb, Zn, and Cd regarding the environmental pollution indexes. Ingestion was the main route of exposure to heavy metals contained in street dust. The CR for adults and children is less than 1 × 10−6, which means that there is no risk for the population. However, the HI was 10 times higher in children than in adults.

Class I MHC Polymorphisms Associated with Type 2 Diabetes in the Mexican Population.

Type 2 diabetes (T2D) has been linked to the expression of Human Leukocyte Antigens, principally to the Major Histocompatibility Complex Class II, with only scarce reports of Major Histocompatibility Complex Class I in specific populations. The objective of the present work was to explore the presence of polymorphisms in the MHC Class I related to T2D in the Mexican population using the Genome-Wide Association Studies Slim Initiative in Genomic Medicine of the Americas (GWAS SIGMA) database. This database contains information on 3848 Mexican individuals with T2D and 4366 control individuals from the same population without a clinical or hereditary history of the disease. The searching criteria considered a p-value of <0.005 and an odds ratio (OR) of >1.0. Ten novel, statistically significant nucleotide variants were identified: four polymorphisms associated with HLA-A (A*03:01:01:01) and six with HLA-C (C*01:02:01:01). These alleles have a high prevalence in Latin American populations and could potentially be associated with autoimmunity mechanisms related to the development of T2D complications.

Cross-species analysis of LZTR1 loss-of-function mutants demonstrates dependency to RIT1 orthologs.

RAS GTPases are highly conserved proteins involved in the regulation of mitogenic signaling. We have previously described a novel Cullin 3 RING E3 ubiquitin ligase complex formed by the substrate adaptor protein LZTR1 that binds, ubiquitinates, and promotes proteasomal degradation of the RAS GTPase RIT1. In addition, others have described that this complex is also responsible for the ubiquitination of classical RAS GTPases. Here, we have analyzed the phenotypes of Lztr1 loss-of-function mutants in both fruit flies and mice and have demonstrated a biochemical preference for their RIT1 orthologs. Moreover, we show that Lztr1 is haplosufficient in mice and that embryonic lethality of the homozygous null allele can be rescued by deletion of Rit1. Overall, our results indicate that, in model organisms, RIT1 orthologs are the preferred substrates of LZTR1.

Regional anesthesia in patients with Charcot-Marie-Tooth disease: a historical cohort study of 53 patients.

PURPOSE: Anesthetic management for patients with Charcot-Marie-Tooth disease (CMT) is controversial. Description of the use of regional anesthesia (RA) in patients with CMT is limited. Regional anesthesia has traditionally been avoided because of risk of nerve injury. We retrospectively reviewed patients with CMT who received RA at our institution. METHODS: We performed a historical cohort study of all patients with CMT who received RA from 30 April 2010 to 30 April 2020 within our institution. Charts were reviewed for information on demographics, RA procedures, perioperative variables, evidence of neurologic complications, post-RA neurology consults, and perioperative electromyography (EMG) results. Electromyographs were reviewed by a neurologist who was blinded to the surgical and RA details. RESULTS: Fifty-three patients received a total of 132 regional anesthetics during the study period. Twenty-five patients received RA on more than one occasion. Fifty-five EMGs and 14 postoperative neurology consults were performed. Two patients had neurology consults with peripheral nerve block (PNB) distribution complaints years later. Neither attributed the complaints to the PNB. The other neurology consults were for unrelated complaints. No EMG results suggested injury related to PNB. CONCLUSION: This study found no evidence of documented neurologic complications or an increased risk of nerve injury related to RA in CMT patients.

RéSUMé: OBJECTIF: La prise en charge anesthésique des patients atteints de la maladie de Charcot-Marie-Tooth (CMT) est controversée. Les descriptions de l'utilisation de l'anesthésie régionale (AR) chez les patients atteints de CMT sont limitées. L'anesthésie régionale est traditionnellement évitée en raison du risque de lésion nerveuse. Nous avons rétrospectivement passé en revue les dossiers des patients atteints de CMT ayant reçu une AR dans notre établissement. MéTHODE: Nous avons réalisé une étude de cohorte historique de tous les patients atteints de CMT ayant reçu une AR entre le 30 avril 2010 et le 30 avril 2020 au sein de notre établissement. Les dossiers ont été passés en revue pour en tirer des renseignements sur les données démographiques, les interventions d'AR, les variables périopératoires, les signes de complications neurologiques, les consultations en neurologie post-AR et les résultats de l'électromyographie (EMG) périopératoire. Les électromyographes ont été examinés par un neurologue qui n'avait pas accès aux détails concernant la chirurgie et l'AR. RéSULTATS: Cinquante-trois patients ont reçu un total de 132 anesthésies régionales au cours de la période d'étude. Vingt-cinq patients ont reçu une AR à plus d'une occasion. Cinquante-cinq EMG et 14 consultations postopératoires en neurologie ont été effectuées. Deux patients ont consulté en neurologie après s'être plaints de la distribution du bloc nerveux périphérique (BNP) des années plus tard. Ni l'un ni l'autre n'a attribué ces problèmes au BNP. Les autres consultations en neurologie concernaient des plaintes non liées au BNP. Aucun résultat d'EMG n'a suggéré de lésion liée au BNP. CONCLUSION: Cette étude n'a trouvé aucune preuve de complications neurologiques documentées ou d'un risque accru de lésion nerveuse liée à l'AR chez les patients atteints de CMT.

A Deep-Learning Based Posture Detection System for Preventing Telework-Related Musculoskeletal Disorders.

The change from face-to-face work to teleworking caused by the pandemic has induced multiple workers to spend more time than usual in front of a computer; in addition, the sudden installation of workstations in homes means that not all of them meet the necessary characteristics for the worker to be able to position himself/herself comfortably with the correct posture in front of their computer. Furthermore, from the point of view of the medical personnel in charge of occupational risk prevention, an automated tool able to quantify the degree of incorrectness of a postural habit in a worker is needed. For this purpose, in this work, a system based on the postural detection of the worker is designed, implemented and tested, using a specialized hardware system that processes video in real time through convolutional neural networks. This system is capable of detecting the posture of the neck, shoulders and arms, providing recommendations to the worker in order to prevent possible health problems, due to poor posture. The results of the proposed system show that this video processing can be carried out in real time (up to 25 processed frames/sec) with a low power consumption (less than 10 watts) using specialized hardware, obtaining an accuracy of over 80% in terms of the pattern detected.

RAS interaction with Sin1 is dispensable for mTORC2 assembly and activity.

RAS proteins are molecular switches that interact with effector proteins when bound to guanosine triphosphate, stimulating downstream signaling in response to multiple stimuli. Although several canonical downstream effectors have been extensively studied and tested as potential targets for RAS-driven cancers, many of these remain poorly characterized. In this study, we undertook a biochemical and structural approach to further study the role of Sin1 as a RAS effector. Sin1 interacted predominantly with KRAS isoform 4A in cells through an atypical RAS-binding domain that we have characterized by X-ray crystallography. Despite the essential role of Sin1 in the assembly and activity of mTORC2, we find that the interaction with RAS is not required for these functions. Cells and mice expressing a mutant of Sin1 that is unable to bind RAS are proficient for activation and assembly of mTORC2. Our results suggest that Sin1 is a bona fide RAS effector that regulates downstream signaling in an mTORC2-independent manner.

The RAS GTPase RIT1 compromises mitotic fidelity through spindle assembly checkpoint suppression.

The spindle assembly checkpoint (SAC) functions as a sensor of unattached kinetochores that delays mitotic progression into anaphase until proper chromosome segregation is guaranteed.1,2 Disruptions to this safety mechanism lead to genomic instability and aneuploidy, which serve as the genetic cause of embryonic demise, congenital birth defects, intellectual disability, and cancer.3,4 However, despite the understanding of the fundamental mechanisms that control the SAC, it remains unknown how signaling pathways directly interact with and regulate the mitotic checkpoint activity. In response to extracellular stimuli, a diverse network of signaling pathways involved in cell growth, survival, and differentiation are activated, and this process is prominently regulated by the Ras family of small guanosine triphosphatases (GTPases).5 Here we show that RIT1, a Ras-related GTPase that regulates cell survival and stress response,6 is essential for timely progression through mitosis and proper chromosome segregation. RIT1 dissociates from the plasma membrane (PM) during mitosis and interacts directly with SAC proteins MAD2 and p31comet in a process that is regulated by cyclin-dependent kinase 1 (CDK1) activity. Furthermore, pathogenic levels of RIT1 silence the SAC and accelerate transit through mitosis by sequestering MAD2 from the mitotic checkpoint complex (MCC). Moreover, SAC suppression by pathogenic RIT1 promotes chromosome segregation errors and aneuploidy. Our results highlight a unique function of RIT1 compared to other Ras GTPases and elucidate a direct link between a signaling pathway and the SAC through a novel regulatory mechanism.

Provirus reactivation is impaired in HIV-1 infected individuals on treatment with dasatinib and antiretroviral therapy.

The latent viral reservoir formed by HIV-1, mainly in CD4 + T cells, is responsible for the failure of antiretroviral therapy (ART) to achieve a complete elimination of the virus in infected individuals. We previously determined that CD4 + T cells from individuals with chronic myeloid leukemia (CML) on treatment with dasatinib are resistant to HIV-1 infection ex vivo. The main mechanism for this antiviral effect is the preservation of SAMHD1 activity. In this study, we aimed to evaluate the impact of dasatinib on the viral reservoir of HIV-infected individuals with CML who were on simultaneous treatment with ART and dasatinib. Due to the low estimated incidence of HIV-1 infection and CML (1:65,000), three male individuals were recruited in Spain and Germany. These individuals had been on treatment with standard ART and dasatinib for median 1.3 years (IQR 1.3-5.3 years). Reservoir size and composition in PBMCs from these individuals was analyzed in comparison with HIV-infected individuals on triple ART regimen and undetectable viremia. The frequency of latently infected cells was reduced more than 5-fold in these individuals. The reactivation of proviruses from these cells was reduced more than 4-fold and, upon activation, SAMHD1 phosphorylation was reduced 40-fold. Plasma levels of the homeostatic cytokine IL-7 and CD4 effector subpopulations TEM and TEMRA in peripheral blood were also reduced. Therefore, treatment of HIV-infected individuals with dasatinib as adjuvant of ART could disturb the reservoir reactivation and reseeding, which might have a beneficial impact to reduce its size.

Wildlife Monitoring on the Edge: A Performance Evaluation of Embedded Neural Networks on Microcontrollers for Animal Behavior Classification.

Monitoring animals' behavior living in wild or semi-wild environments is a very interesting subject for biologists who work with them. The difficulty and cost of implanting electronic devices in this kind of animals suggest that these devices must be robust and have low power consumption to increase their battery life as much as possible. Designing a custom smart device that can detect multiple animal behaviors and that meets the mentioned restrictions presents a major challenge that is addressed in this work. We propose an edge-computing solution, which embeds an ANN in a microcontroller that collects data from an IMU sensor to detect three different horse gaits. All the computation is performed in the microcontroller to reduce the amount of data transmitted via wireless radio, since sending information is one of the most power-consuming tasks in this type of devices. Multiples ANNs were implemented and deployed in different microcontroller architectures in order to find the best balance between energy consumption and computing performance. The results show that the embedded networks obtain up to 97.96% ± 1.42% accuracy, achieving an energy efficiency of 450 Mops/s/watt.