Rapid adaptation to CDK2 inhibition exposes intrinsic cell-cycle plasticity.

CDK2 is a core cell-cycle kinase that phosphorylates many substrates to drive progression through the cell cycle. CDK2 is hyperactivated in multiple cancers and is therefore an attractive therapeutic target. Here, we use several CDK2 inhibitors in clinical development to interrogate CDK2 substrate phosphorylation, cell-cycle progression, and drug adaptation in preclinical models. Whereas CDK1 is known to compensate for loss of CDK2 in Cdk2-/- mice, this is not true of acute inhibition of CDK2. Upon CDK2 inhibition, cells exhibit a rapid loss of substrate phosphorylation that rebounds within several hours. CDK4/6 activity backstops inhibition of CDK2 and sustains the proliferative program by maintaining Rb1 hyperphosphorylation, active E2F transcription, and cyclin A2 expression, enabling re-activation of CDK2 in the presence of drug. Our results augment our understanding of CDK plasticity and indicate that co-inhibition of CDK2 and CDK4/6 may be required to suppress adaptation to CDK2 inhibitors currently under clinical assessment.

Ultrahigh-charge electron beams from laser-irradiated solid surface.

Compact acceleration of a tightly collimated relativistic electron beam with high charge from a laser-plasma interaction has many unique applications. However, currently the well-known schemes, including laser wakefield acceleration from gases and vacuum laser acceleration from solids, often produce electron beams either with low charge or with large divergence angles. In this work, we report the generation of highly collimated electron beams with a divergence angle of a few degrees, nonthermal spectra peaked at the megaelectronvolt level, and extremely high charge (∼100 nC) via a powerful subpicosecond laser pulse interacting with a solid target in grazing incidence. Particle-in-cell simulations illustrate a direct laser acceleration scenario, in which the self-filamentation is triggered in a large-scale near-critical-density plasma and electron bunches are accelerated periodically and collimated by the ultraintense electromagnetic field. The energy density of such electron beams in high-Z materials reaches to [Formula: see text], making it a promising tool to drive warm or even hot dense matter states.

Reciprocal regulation of amino acid import and epigenetic state through Lat1 and EZH2.

Lat1 (SLC7A5) is an amino acid transporter often required for tumor cell import of essential amino acids (AA) including Methionine (Met). Met is the obligate precursor of S-adenosylmethionine (SAM), the methyl donor utilized by all methyltransferases including the polycomb repressor complex (PRC2)-specific EZH2. Cell populations sorted for surface Lat1 exhibit activated EZH2, enrichment for Met-cycle intermediates, and aggressive tumor growth in mice. In agreement, EZH2 and Lat1 expression are co-regulated in models of cancer cell differentiation and co-expression is observed at the invasive front of human lung tumors. EZH2 knockdown or small-molecule inhibition leads to de-repression of RXRα resulting in reduced Lat1 expression. Our results describe a Lat1-EZH2 positive feedback loop illustrated by AA depletion or Lat1 knockdown resulting in SAM reduction and concomitant reduction in EZH2 activity. shRNA-mediated knockdown of Lat1 results in tumor growth inhibition and points to Lat1 as a potential therapeutic target.

Targeting S-adenosylmethionine biosynthesis with a novel allosteric inhibitor of Mat2A.

S-Adenosyl-L-methionine (SAM) is an enzyme cofactor used in methyl transfer reactions and polyamine biosynthesis. The biosynthesis of SAM from ATP and L-methionine is performed by the methionine adenosyltransferase enzyme family (Mat; EC 2.5.1.6). Human methionine adenosyltransferase 2A (Mat2A), the extrahepatic isoform, is often deregulated in cancer. We identified a Mat2A inhibitor, PF-9366, that binds an allosteric site on Mat2A that overlaps with the binding site for the Mat2A regulator, Mat2B. Studies exploiting PF-9366 suggested a general mode of Mat2A allosteric regulation. Allosteric binding of PF-9366 or Mat2B altered the Mat2A active site, resulting in increased substrate affinity and decreased enzyme turnover. These data support a model whereby Mat2B functions as an inhibitor of Mat2A activity when methionine or SAM levels are high, yet functions as an activator of Mat2A when methionine or SAM levels are low. The ramification of Mat2A activity modulation in cancer cells is also described.

Hashtag #TBI: A content and network data analysis of tweets about Traumatic Brain Injury.

OBJECTIVE: The aims of this study were to: (a) determine how Twitter is used by people with traumatic brain injury (TBI) and TBI organisations, (b) analyse the Twitter networks and content of tweets tagged with TBI-related hashtags, and (c) identify any challenges people with TBI encounter in using Twitter. RESEARCH DESIGN: Mixed methods in a Twitter hashtag study. METHODS: Mixed methods in a Twitter hashtag study. Tweets tagged with TBI-related hashtags were harvested from the Twitter website over a one-month period in 2016 and analysed qualitatively and quantitatively. RESULTS: The sample of 29,199 tweets included tweets sent by 893 @users, 219 of whom had a brain injury. Twitter was used to: (a) discuss health issues, (b) raise awareness of TBI, (c) talk about life after TBI, (d) talk about sport and concussion, and (e) communicate inspirational messages. CONCLUSIONS: Twitter is an important platform for research and knowledge translation on TBI, and for hearing the voices of people with TBI as they express their personal views and stories of living with TBI and become more visible and influential in Twitter communities. TBI clinicians could use these narratives of people with TBI in Twitter to develop more effective and personally meaningful rehabilitation goals.

A call for innovative social media research in the field of augmentative and alternative communication.

Augmentative and alternative communication (AAC) social media research is relatively new, and is built on a foundation of research on use of the Internet and social media by people with communication disabilities. Although the field is expanding to include a range of people who use AAC, there are limitations and gaps in research that will need to be addressed in order to keep pace with the rapid evolution of social media connectivity in assistive communication technologies. In this paper, we consider the aims, scope, and methodologies of AAC social media research, with a focus on social network sites. Lack of detailed attention to specific social network sites and little use of social media data limits the extent to which findings can be confirmed. Increased use of social media data across a range of platforms, including Instagram and YouTube, would provide important insights into the lives of people who use AAC and the ways in which they and their supporters use social media. New directions for AAC social media research are presented in line with those discussed at the social media research symposium at the International Society for Augmentative and Alternative Communication in Toronto, Canada, on August 12, 2016.

Craving inclusion: a systematic review on the experiences and needs of people with disability eating out.

Purpose: To systematically review the research relating to views and experiences of people with disability eating out in cafés, restaurants, and other settings; and identify factors that impede or enhance accessibility of eating out experiences, inform future inclusive research, and guide policy development.Materials and Methods: This study involved systematic search and review procedures with qualitative metasynthesis of the barriers to and facilitators for participation and inclusion in eating/dining-out activities. In total, 36 studies were included.Results: Most studies reviewed related to people with physical or sensory disability eating out, with few studies examining the dining experiences of adults with intellectual or developmental disability, swallowing disability, or communication disability. People with disability encountered negative attitudes and problems with physical and communicative access to the venue. Staff lacked knowledge of disability. Improvements in the design of dining spaces, consultation with the disability community, and staff training are needed.Conclusion: People with disability may need support for inclusion in eating out activities, as they encounter a range of barriers to eating out. Further research within and across both a wide range of populations with disability and eating out settings could guide policy and practice and help develop training for hospitality staff.

Some people with disability require support for increased self-determination and self-advocacy to access eating out experiences satisfactorily.Goals and strategies to increase access and participation in eating out activities for people with disability should include attention to the environment and hospitality venues and to staff training.Rehabilitation professionals have a role in training hospitality staff about disability access and inclusion in eating out activities.To enhance community inclusion and participation, rehabilitation professionals could focus more on the skills and strategies needed for people with disability to participate in eating out activities.Rehabilitation professionals could implement a range of facilitators that might strengthen participation in eating out activities for people with disability.

Longitudinal multi-omics study of palbociclib resistance in HR-positive/HER2-negative metastatic breast cancer.

BACKGROUND: Cyclin-dependent kinase 4/6 inhibitor (CDK4/6) therapy plus endocrine therapy (ET) is an effective treatment for patients with hormone receptor-positive/human epidermal receptor 2-negative metastatic breast cancer (HR+/HER2- MBC); however, resistance is common and poorly understood. A comprehensive genomic and transcriptomic analysis of pretreatment and post-treatment tumors from patients receiving palbociclib plus ET was performed to delineate molecular mechanisms of drug resistance. METHODS: Tissue was collected from 89 patients with HR+/HER2- MBC, including those with recurrent and/or metastatic disease, receiving palbociclib plus an aromatase inhibitor or fulvestrant at Samsung Medical Center and Seoul National University Hospital from 2017 to 2020. Tumor biopsy and blood samples obtained at pretreatment, on-treatment (6 weeks and/or 12 weeks), and post-progression underwent RNA sequencing and whole-exome sequencing. Cox regression analysis was performed to identify the clinical and genomic variables associated with progression-free survival. RESULTS: Novel markers associated with poor prognosis, including genomic scar features caused by homologous repair deficiency (HRD), estrogen response signatures, and four prognostic clusters with distinct molecular features were identified. Tumors with TP53 mutations co-occurring with a unique HRD-high cluster responded poorly to palbociclib plus ET. Comparisons of paired pre- and post-treatment samples revealed that tumors became enriched in APOBEC mutation signatures, and many switched to aggressive molecular subtypes with estrogen-independent characteristics. We identified frequent genomic alterations upon disease progression in RB1, ESR1, PTEN, and KMT2C. CONCLUSIONS: We identified novel molecular features associated with poor prognosis and molecular mechanisms that could be targeted to overcome resistance to CKD4/6 plus ET. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03401359. The trial was posted on 18 January 2018 and registered prospectively.

Views on the usability, design, and future possibilities of a 3D food printer for people with dysphagia: outcomes of an immersive experience.

PURPOSE: Although 3D food printing is expected to enable the creation of visually appealing pureed food for people with disability and dysphagia, little is known about the user experience in engaging with 3D food printing or the feasibility of use with populations who need texture-modified foods. The aim of this study was to explore the feasibility and usability of using domestic-scale 3D food printer as an assistive technology to print pureed food into attractive food shapes for people with dysphagia. MATERIALS AND METHODS: In total, 16 participants engaged in the unfamiliar, novel process of using a domestic-scale 3D food printer (choosing, printing, tasting), designed for printing pureed food, and discussed their impressions in focus group or individual interviews. RESULTS AND CONCLUSIONS: Overall, results demonstrated that informed experts who were novice users perceived the 3D food printing process to be fun but time consuming, and that 3D food printers might not yet be suitable for people with dysphagia or their supporters. Slow response time, lack of user feedback, scant detail on the appropriate recipes for the pureed food to create a successful print, and small font on the user panel interface were perceived as barriers to accessibility for people with disability and older people. Participants expected more interactive elements and feedback from the device, particularly in relation to resolving printer or user errors. This study will inform future usability trials and food safety research into 3D printed foods for people with disability and dysphagia. IMPLICATIONS FOR REHABILITATION3D food printers potentially have a role as an assistive technology in the preparation of texture-modified foods for people with disability and dysphagia.To increase feasibility, 3D food printers should be co-designed with people with disability and their supporters and health professionals working in the field of dysphagia and rehabilitation.Experts struggled to be able to print 3D pureed shapes owing to relatively low usability of the 3D food printer tested with problems using the interface and resolving problems in the print.3D food printing is a fun and novel activity and may help to engage people with disability and dysphagia in making choices around the shape of the food to be printed.

Rehabilitation professionals' views on social media use in traumatic brain injury rehabilitation: gatekeepers to participation.

PURPOSE: Rehabilitation professionals support people with traumatic brain injury (TBI) to return to meaningful participation in life and society - which now includes the use of social media. However, the role of health professionals in supporting the use of social media by adults with TBI is not yet known. This study aimed to investigate the experiences and views of rehabilitation professionals on the use of social media by people with TBI during rehabilitation. METHOD: Two focus groups were conducted and analysed qualitatively for content themes. RESULTS: Eleven rehabilitation professionals, including allied health, recreational therapy, and service management, took part in this study. Participants identified potential benefits to people with TBI using social media, including reduced social isolation. However, they expressed concerns about social media risks relating to the vulnerability, exploitation, and reputation management for people with TBI. Rehabilitation professionals viewed their role as being to protect people from these risks of harm, either through imposing restrictions on social media use or responding to problems after these occurred. CONCLUSION: A knowledge translation approach might help guide and support rehabilitation professionals in enabling adults with TBI to safely access and experience the benefits of meaningful engagement in social media during rehabilitation.Implications for rehabilitationRehabilitation professionals can start addressing social media use during collaborative goal setting, in order to support people with traumatic brain injury to use social media successfully during rehabilitation and beyond. To do this, professionals can inquire as to the person's previous social media use and identify priority areas for the person for short- and long-term goals.Rehabilitation targeting social media use should include instruction for participation in social media platforms, providing education and feedback that is positive and constructive, as well as risk management education.Policy and guidance is needed for rehabilitation professionals to more actively support people with traumatic brain injury to access social media for improved participation and inclusion in online communities.Addressing social media goals in rehabilitation should be informed by existing successful traumatic brain injury rehabilitation approaches (e.g., functional rehabilitation) and adopting strategies used in rehabilitation supporting other higher risk goals (e.g., return to driving).

Social Media and People With Traumatic Brain Injury: A Metasynthesis of Research Informing a Framework for Rehabilitation Clinical Practice, Policy, and Training.

Purpose The aim of the study was to investigate the experiences of people with traumatic brain injury (TBI) and rehabilitation professionals in use of social media after TBI. Design Metasynthesis of a multilevel mixed-methods research design was used in the study. Method A qualitative metasynthesis of (a) evidence in the literature regarding the use of communication technologies and social media after TBI, (b) Twitter data and network analysis, (c) interviews with people with TBI (n = 13), (d) focus groups with TBI rehabilitation professionals (n = 11), and (e) a review of current guidance on safe use of social media was conducted. Results People with TBI adopt a trial-and-error approach to using social media. Their meaningful use and a sense of connection enable them to develop social media mastery. TBI rehabilitation professionals' concerns regarding potential risks associated with using social media might lead them to restrict social media use during rehabilitation. Conclusions Access to proactive training in social media use and a supportive network of rehabilitation professionals, family, and friends can enable people with TBI to develop social media mastery through working collaboratively on social media goals. This metasynthesis of research culminates in an evidence-based protocol for assessing and supporting a person with TBI's social media goals to guide clinical practice and future research in the field.

The evolution of cyclin dependent kinase inhibitors in the treatment of cancer.

Introduction: The cell cycle cyclin-dependent kinases (CDKs) play a critical role in controlling the transition between cell cycle phases, as well as cellular transcription. Aberrant CDK activation is common in cancer, and deregulation of the cell cycle a key hallmark of cancer. Although CDK4/6 inhibitors are now a standard-of-care option for first- and second-line HR+/HER2- metastatic breast cancer, resistance inevitably limits their clinical benefit.Areas covered: Early pan-CDK inhibitors targeted the cell cycle and RNA polymerase II phosphorylation, but were complicated by toxicity, providing a rationale and need for the development of selective CDK inhibitors. In this review, we highlight selected recent literature to provide a narrative review summarizing the current CDK inhibitor therapeutic landscape. We detail the challenges associated with targeting CDKs for the treatment of breast and other cancers and review emerging biomarkers that may aid response prediction. We also discuss the risk-benefit ratio for CDK therapy and explore promising combination approaches.Expert opinion: Although CDK inhibitors may stem the proliferation of cancer cells, resistance remains an issue, and currently there are limited biomarkers to predict response to therapy. Ongoing research investigating CDK inhibitors in cancer is of paramount importance to define appropriate and effective treatment regimens.

Discovery of PF-06873600, a CDK2/4/6 Inhibitor for the Treatment of Cancer.

Control of the cell cycle through selective pharmacological inhibition of CDK4/6 has proven beneficial in the treatment of breast cancer. Extending this level of control to additional cell cycle CDK isoforms represents an opportunity to expand to additional tumor types and potentially provide benefits to patients that develop tumors resistant to selective CDK4/6 inhibitors. However, broad-spectrum CDK inhibitors have a long history of failure due to safety concerns. In this approach, we describe the use of structure-based drug design and Free-Wilson analysis to optimize a series of CDK2/4/6 inhibitors. Further, we detail the use of molecular dynamics simulations to provide insights into the basis for selectivity against CDK9. Based on overall potency, selectivity, and ADME profile, PF-06873600 (22) was identified as a candidate for the treatment of cancer and advanced to phase 1 clinical trials.

Expanding control of the tumor cell cycle with a CDK2/4/6 inhibitor.

The CDK4/6 inhibitor, palbociclib (PAL), significantly improves progression-free survival in HR+/HER2- breast cancer when combined with anti-hormonals. We sought to discover PAL resistance mechanisms in preclinical models and through analysis of clinical transcriptome specimens, which coalesced on induction of MYC oncogene and Cyclin E/CDK2 activity. We propose that targeting the G1 kinases CDK2, CDK4, and CDK6 with a small-molecule overcomes resistance to CDK4/6 inhibition. We describe the pharmacodynamics and efficacy of PF-06873600 (PF3600), a pyridopyrimidine with potent inhibition of CDK2/4/6 activity and efficacy in multiple in vivo tumor models. Together with the clinical analysis, MYC activity predicts (PF3600) efficacy across multiple cell lineages. Finally, we find that CDK2/4/6 inhibition does not compromise tumor-specific immune checkpoint blockade responses in syngeneic models. We anticipate that (PF3600), currently in phase 1 clinical trials, offers a therapeutic option to cancer patients in whom CDK4/6 inhibition is insufficient to alter disease progression.

Palbociclib and Fulvestrant Act in Synergy to Modulate Central Carbon Metabolism in Breast Cancer Cells.

The aims of this study were to determine whether combination chemotherapeutics exhibit a synergistic effect on breast cancer cell metabolism. Palbociclib, is a selective inhibitor of cyclin-dependent kinases 4 and 6, and when patients are treated in combination with fulvestrant, an estrogen receptor antagonist, they have improved progression-free survival. The mechanisms for this survival advantage are not known. Therefore, we analyzed metabolic and transcriptomic changes in MCF-7 cells following single and combination chemotherapy to determine whether selective metabolic pathways are targeted during these different modes of treatment. Individually, the drugs caused metabolic disruption to the same metabolic pathways, however fulvestrant additionally attenuated the pentose phosphate pathway and the production of important coenzymes. A comprehensive effect was observed when the drugs were applied together, confirming the combinatory therapy's synergism in the cell model. This study also highlights the power of merging high-dimensional datasets to unravel mechanisms involved in cancer metabolism and therapy.

mTOR Complex1-S6K1 signaling: at the crossroads of obesity, diabetes and cancer.

Recent studies demonstrate that the mammalian target of rapamycin (mTOR) and its effector, S6 kinase 1 (S6K1), lie at the crossroads of a nutrient-hormonal signaling network that is involved in specific pathological responses, including obesity, diabetes and cancer. mTOR exists in two complexes: mTOR Complex1, which is rapamycin-sensitive and phosphorylates S6K1 and initiation factor 4E binding proteins (4E-BPs), and mTOR Complex2, which is rapamycin-insensitive and phosphorylates protein kinase B (PKB, also known as Akt). Both mTOR complexes are stimulated by mitogens, but only mTOR Complex1 is under the control of nutrient and energy inputs. Thus, to orchestrate the control of homeostatic responses, mTOR Complex1 must integrate signals from distinct cues. Here, we review recent findings concerning the regulation and pathophysiology associated with mTOR Complex1 and S6K1.

Using Twitter to access the human right of communication for people who use Augmentative and Alternative Communication (AAC).

PURPOSE: Articles 19, 26 and 27 of the Universal Declaration of Human Rights and Articles 4, 9 and 21 of the Convention on the Rights of Persons with Disabilities promote the human rights of communication, education, use of technology and access to information. Social media is an important form of online communication, and Twitter increases users' visibility, influence and reach online. The aim of this sociotechnical research was to determine the impact of teaching three people who use Augmentative and Alternative Communication (AAC) to use Twitter. METHOD: Three participants were trained in ways of using Twitter strategically. Data collected from participants' Twitter profiles were examined to determine the impact of training on Twitter follower count, frequency of tweeting, tweet content and the development of social networks. Data were also examined using (1) KH Coder software analysis and visualisation of co-occurring networks in the text data, based on word frequencies; and (2) Gephi software analysis to show the Twitter network for each participant. RESULT: Two participants showed an improvement in Twitter skills and strategies. CONCLUSIONS: Twitter can be used to improve social connectedness of people who use AAC, and should not be overlooked in relation to communication rights.

A versatile drug delivery system targeting senescent cells.

Senescent cells accumulate in multiple aging-associated diseases, and eliminating these cells has recently emerged as a promising therapeutic approach. Here, we take advantage of the high lysosomal ß-galactosidase activity of senescent cells to design a drug delivery system based on the encapsulation of drugs with galacto-oligosaccharides. We show that gal-encapsulated fluorophores are preferentially released within senescent cells in mice. In a model of chemotherapy-induced senescence, gal-encapsulated cytotoxic drugs target senescent tumor cells and improve tumor xenograft regression in combination with palbociclib. Moreover, in a model of pulmonary fibrosis in mice, gal-encapsulated cytotoxics target senescent cells, reducing collagen deposition and restoring pulmonary function. Finally, gal-encapsulation reduces the toxic side effects of the cytotoxic drugs. Drug delivery into senescent cells opens new diagnostic and therapeutic applications for senescence-associated disorders.

Disruption of the mouse mTOR gene leads to early postimplantation lethality and prohibits embryonic stem cell development.

The mammalian target of rapamycin (mTOR) is a key component of a signaling pathway which integrates inputs from nutrients and growth factors to regulate cell growth. Recent studies demonstrated that mice harboring an ethylnitrosourea-induced mutation in the gene encoding mTOR die at embryonic day 12.5 (E12.5). However, others have shown that the treatment of E4.5 blastocysts with rapamycin blocks trophoblast outgrowth, suggesting that the absence of mTOR should lead to embryonic lethality at an earlier stage. To resolve this discrepancy, we set out to disrupt the mTOR gene and analyze the outcome in both heterozygous and homozygous settings. Heterozygous mTOR (mTOR(+/-)) mice do not display any overt phenotype, although mouse embryonic fibroblasts derived from these mice show a 50% reduction in mTOR protein levels and phosphorylation of S6 kinase 1 T389, a site whose phosphorylation is directly mediated by mTOR. However, S6 phosphorylation, raptor levels, cell size, and cell cycle transit times are not diminished in these cells. In contrast to the situation in mTOR(+/-) mice, embryonic development of homozygous mTOR(-/-) mice appears to be arrested at E5.5; such embryos are severely runted and display an aberrant developmental phenotype. The ability of these embryos to implant corresponds to a limited level of trophoblast outgrowth in vitro, reflecting a maternal mRNA contribution, which has been shown to persist during preimplantation development. Moreover, mTOR(-/-) embryos display a lesion in inner cell mass proliferation, consistent with the inability to establish embryonic stem cells from mTOR(-/-) embryos.

The amino acid sensitive TOR pathway from yeast to mammals.

The target of rapamycin (TOR) is an ancient effector of cell growth that integrates signals from growth factors and nutrients. Two downstream effectors of mammalian TOR, the translational components S6K1 and 4EBP1, are commonly used as reporters of mTOR activity. The conical signaling cascade initiated by growth factors is mediated by PI3K, PKB, TSC1/2 and Rheb. However, the process through which nutrients, i.e., amino acids, activate mTOR remains largely unknown. Evidence exists for both an intracellular and/or a membrane bound sensor for amino acid mediated mTOR activation. Research in eukaryotic models, has implicated amino acid transporters as nutrient sensors. This review describes recent advances in nutrient signaling that impinge on mTOR and its targets including hVps34, class III PI3K, a transducer of nutrient availability to mTOR.