The PI3K Pathway in Human Disease.

Phosphoinositide 3-kinase (PI3K) activity is stimulated by diverse oncogenes and growth factor receptors, and elevated PI3K signaling is considered a hallmark of cancer. Many PI3K pathway-targeted therapies have been tested in oncology trials, resulting in regulatory approval of one isoform-selective inhibitor (idelalisib) for treatment of certain blood cancers and a variety of other agents at different stages of development. In parallel to PI3K research by cancer biologists, investigations in other fields have uncovered exciting and often unpredicted roles for PI3K catalytic and regulatory subunits in normal cell function and in disease. Many of these functions impinge upon oncology by influencing the efficacy and toxicity of PI3K-targeted therapies. Here we provide a perspective on the roles of class I PI3Ks in the regulation of cellular metabolism and in immune system functions, two topics closely intertwined with cancer biology. We also discuss recent progress developing PI3K-targeted therapies for treatment of cancer and other diseases.

Circling back to PTEN: Fumarate inhibits canonical tumor suppressor.

Ge et al. (2022) describes an inhibitory, post-translational modification of PTEN at C211 by fumarate, which offers new insight into the integration of PI3K signaling and metabolism via a potential feedforward regulatory mechanism involving a PI3K-glucose-fumarate-PTEN axis.

An atlas of substrate specificities for the human serine/threonine kinome.

Protein phosphorylation is one of the most widespread post-translational modifications in biology1,2. With advances in mass-spectrometry-based phosphoproteomics, 90,000 sites of serine and threonine phosphorylation have so far been identified, and several thousand have been associated with human diseases and biological processes3,4. For the vast majority of phosphorylation events, it is not yet known which of the more than 300 protein serine/threonine (Ser/Thr) kinases encoded in the human genome are responsible3. Here we used synthetic peptide libraries to profile the substrate sequence specificity of 303 Ser/Thr kinases, comprising more than 84% of those predicted to be active in humans. Viewed in its entirety, the substrate specificity of the kinome was substantially more diverse than expected and was driven extensively by negative selectivity. We used our kinome-wide dataset to computationally annotate and identify the kinases capable of phosphorylating every reported phosphorylation site in the human Ser/Thr phosphoproteome. For the small minority of phosphosites for which the putative protein kinases involved have been previously reported, our predictions were in excellent agreement. When this approach was applied to examine the signalling response of tissues and cell lines to hormones, growth factors, targeted inhibitors and environmental or genetic perturbations, it revealed unexpected insights into pathway complexity and compensation. Overall, these studies reveal the intrinsic substrate specificity of the human Ser/Thr kinome, illuminate cellular signalling responses and provide a resource to link phosphorylation events to biological pathways.

PI3K drives the de novo synthesis of coenzyme A from vitamin B5.

In response to hormones and growth factors, the class I phosphoinositide-3-kinase (PI3K) signalling network functions as a major regulator of metabolism and growth, governing cellular nutrient uptake, energy generation, reducing cofactor production and macromolecule biosynthesis1. Many of the driver mutations in cancer with the highest recurrence, including in receptor tyrosine kinases, Ras, PTEN and PI3K, pathologically activate PI3K signalling2,3. However, our understanding of the core metabolic program controlled by PI3K is almost certainly incomplete. Here, using mass-spectrometry-based metabolomics and isotope tracing, we show that PI3K signalling stimulates the de novo synthesis of one of the most pivotal metabolic cofactors: coenzyme A (CoA). CoA is the major carrier of activated acyl groups in cells4,5 and is synthesized from cysteine, ATP and the essential nutrient vitamin B5 (also known as pantothenate)6,7. We identify pantothenate kinase 2 (PANK2) and PANK4 as substrates of the PI3K effector kinase AKT8. Although PANK2 is known to catalyse the rate-determining first step of CoA synthesis, we find that the minimally characterized but highly conserved PANK49 is a rate-limiting suppressor of CoA synthesis through its metabolite phosphatase activity. Phosphorylation of PANK4 by AKT relieves this suppression. Ultimately, the PI3K-PANK4 axis regulates the abundance of acetyl-CoA and other acyl-CoAs, CoA-dependent processes such as lipid metabolism and proliferation. We propose that these regulatory mechanisms coordinate cellular CoA supplies with the demands of hormone/growth-factor-driven or oncogene-driven metabolism and growth.

Cystic Fibrosis Transmembrane Conductance Regulator Attaches Tumor Suppressor PTEN to the Membrane and Promotes Anti Pseudomonas aeruginosa Immunity.

The tumor suppressor PTEN controls cell proliferation by regulating phosphatidylinositol-3-kinase (PI3K) activity, but the participation of PTEN in host defense against bacterial infection is less well understood. Anti-inflammatory PI3K-Akt signaling is suppressed in patients with cystic fibrosis (CF), a disease characterized by hyper-inflammatory responses to airway infection. We found that Ptenl-/- mice, which lack the NH2-amino terminal splice variant of PTEN, were unable to eradicate Pseudomonas aeruginosa from the airways and could not generate sufficient anti-inflammatory PI3K activity, similar to what is observed in CF. PTEN and the CF transmembrane conductance regulator (CFTR) interacted directly and this interaction was necessary to position PTEN at the membrane. CF patients under corrector-potentiator therapy, which enhances CFTR transport to the membrane, have increased PTEN amounts. These findings suggest that improved CFTR trafficking could enhance P. aeruginosa clearance from the CF airway by activating PTEN-mediated anti-bacterial responses and might represent a therapeutic strategy.

Association of Surgical Approaches and Outcomes in Total Mesorectal Excision and Margin Status for Rectal Cancer.

INTRODUCTION: Despite being a key metric with a significant correlation with the outcomes of patients with rectal cancer, the optimal surgical approach for total mesorectal excision (TME) has not yet been identified. The aim of this study was to assess the association of the surgical approach on the quality of TME and surgical margins and to characterize the surgical and long-term oncologic outcomes in patients undergoing robotic, laparoscopic, and open TME for rectal cancer. METHODS: Patients with primary, nonmetastatic rectal adenocarcinoma who underwent either lower anterior resection or abdominoperineal resection via robotic (Rob), laparoscopic (Lap), or open approaches were selected from the US Rectal Cancer Consortium database (2007-2017). Quasi-Poisson regression analysis with backward selection was used to investigate the relationship between the surgical approach and outcomes of interest. RESULTS: Among the 664 patients included in the study, the distribution of surgical approaches was as follows: 351 (52.9%) underwent TME via the open approach, 159 (23.9%) via the robotic approach, and 154 (23.2%) via the laparoscopic approach. There were no significant differences in baseline demographics among the three cohorts. The laparoscopic cohort had fewer patients with low rectal cancer (<6 cm from the anal verge) than the robotic and open cohorts (Lap 28.6% versus Rob 59.1% versus Open 45.6%, P = 0.015). Patients who underwent Rob and Lap TME had lower intraoperative blood loss compared with the Open approach (Rob 200 mL [Q1, Q3: 100.0, 300.0] versus Lap 150 mL [Q1, Q3: 75.0, 250.0] versus Open 300 mL [Q1, Q3: 150.0, 600.0], P < 0.001). There was no difference in the operative time (Rob 243 min [Q1, Q3: 203.8, 300.2] versus Lap 241 min [Q1, Q3: 186, 336] versus Open 226 min [Q1, Q3: 178, 315.8], P = 0.309) between the three approaches. Postoperative length of stay was shorter with robotic and laparoscopic approach compared to open approach (Rob 5.0 d [Q1, Q3: 4, 8.2] versus Lap 5 d [Q1, Q3: 4, 8] versus Open 7.0 d [Q1, Q3: 5, 9], P < 0.001). There was no statistically significant difference in the quality of TME between the robotic, laparoscopic, and open approaches (79.2%, 64.9%, and 64.7%, respectively; P = 0.46). The margin positivity rate, a composite of circumferential margin and distal margin, was higher with the robotic and open approaches than with the laparoscopic approach (Rob 8.2% versus Open 6.6% versus Lap 1.9%, P = 0.17), Rob versus Lap (odds ratio 0.21; 95% confidence interval 0.05, 0.83) and Rob versus Open (odds ratio 0.5; 95% confidence interval 0.22, 1.12). There was no difference in long-term survival, including overall survival and recurrence-free survival, between patients who underwent robotic, laparoscopic, or open TME (Figure 1). CONCLUSIONS: In patients undergoing surgery with curative intent for rectal cancer, we did not observe a difference in the quality of TME between the robotic, laparoscopic, or open approaches. Robotic and open TME compared to laparoscopic TME were associated with higher margin positivity rates in our study. This was likely due to the higher percentage of low rectal cancers in the robotic and open cohorts. We also reported no significant differences in overall survival and recurrence-free survival between the aforementioned surgical techniques.

Suppression of insulin feedback enhances the efficacy of PI3K inhibitors.

Mutations in PIK3CA, which encodes the p110α subunit of the insulin-activated phosphatidylinositol-3 kinase (PI3K), and loss of function mutations in PTEN, which encodes a phosphatase that degrades the phosphoinositide lipids generated by PI3K, are among the most frequent events in human cancers1,2. However, pharmacological inhibition of PI3K has resulted in variable clinical responses, raising the possibility of an inherent mechanism of resistance to treatment. As p110α mediates virtually all cellular responses to insulin, targeted inhibition of this enzyme disrupts glucose metabolism in multiple tissues. For example, blocking insulin signalling promotes glycogen breakdown in the liver and prevents glucose uptake in the skeletal muscle and adipose tissue, resulting in transient hyperglycaemia within a few hours of PI3K inhibition. The effect is usually transient because compensatory insulin release from the pancreas (insulin feedback) restores normal glucose homeostasis3. However, the hyperglycaemia may be exacerbated or prolonged in patients with any degree of insulin resistance and, in these cases, necessitates discontinuation of therapy3-6. We hypothesized that insulin feedback induced by PI3K inhibitors may reactivate the PI3K-mTOR signalling axis in tumours, thereby compromising treatment effectiveness7,8. Here we show, in several model tumours in mice, that systemic glucose-insulin feedback caused by targeted inhibition of this pathway is sufficient to activate PI3K signalling, even in the presence of PI3K inhibitors. This insulin feedback can be prevented using dietary or pharmaceutical approaches, which greatly enhance the efficacy/toxicity ratios of PI3K inhibitors. These findings have direct clinical implications for the multiple p110α inhibitors that are in clinical trials and provide a way to increase treatment efficacy for patients with many types of tumour.

Publisher Correction: Suppression of insulin feedback enhances the efficacy of PI3K inhibitors.

In this Letter, author Xing Du was incorrectly listed as Du Xing; this has been corrected online.

Inhibitors of cullin-RING E3 ubiquitin ligase 4 with antitumor potential.

Cullin-RING (really intersting new gene) E3 ubiquitin ligases (CRLs) are the largest E3 family and direct numerous protein substrates for proteasomal degradation, thereby impacting a myriad of physiological and pathological processes including cancer. To date, there are no reported small-molecule inhibitors of the catalytic activity of CRLs. Here, we describe high-throughput screening and medicinal chemistry optimization efforts that led to the identification of two compounds, 33-11 and KH-4-43, which inhibit E3 CRL4 and exhibit antitumor potential. These compounds bind to CRL4's core catalytic complex, inhibit CRL4-mediated ubiquitination, and cause stabilization of CRL4's substrate CDT1 in cells. Treatment with 33-11 or KH-4-43 in a panel of 36 tumor cell lines revealed cytotoxicity. The antitumor activity was validated by the ability of the compounds to suppress the growth of human tumor xenografts in mice. Mechanistically, the compounds' cytotoxicity was linked to aberrant accumulation of CDT1 that is known to trigger apoptosis. Moreover, a subset of tumor cells was found to express cullin4 proteins at levels as much as 70-fold lower than those in other tumor lines. The low-cullin4-expressing tumor cells appeared to exhibit increased sensitivity to 33-11/KH-4-43, raising a provocative hypothesis for the role of low E3 abundance as a cancer vulnerability.

CD44 alternative splicing senses intragenic DNA methylation in tumors via direct and indirect mechanisms.

DNA methylation (meDNA) is a modulator of alternative splicing, and splicing perturbations are involved in tumorigenesis nearly as frequently as DNA mutations. However, the impact of meDNA on tumorigenesis via splicing-mediated mechanisms has not been thoroughly explored. Here, we found that HCT116 colon carcinoma cells inactivated for the DNA methylases DNMT1/3b undergo a partial epithelial to mesenchymal transition associated with increased CD44 variant exon skipping. These skipping events are directly mediated by the loss of intragenic meDNA and the chromatin factors MBD1/2/3 and HP1γ and are also linked to phosphorylation changes in elongating RNA polymerase II. The role of meDNA in alternative splicing was confirmed by using the dCas9/DNMT3b tool. We further tested whether the meDNA level could have predictive value in the MCF10A model for breast cancer progression and in patients with acute lymphoblastic leukemia (B ALL). We found that a small number of differentially spliced genes, mostly involved in splicing and signal transduction, are correlated with the local modulation of meDNA. Our observations suggest that, although DNA methylation has multiple avenues to affect alternative splicing, its indirect effect may also be mediated through alternative splicing isoforms of these meDNA sensors.

Mortality following mechanical thrombectomy for ischemic stroke in patients with COVID-19.

OBJECTIVES: Multiple prior studies have shown a relationship between COVID-19 and strokes; further, COVID-19 has been shown to influence both time-to-thrombectomy and overall thrombectomy rates. Using large-scale, recently released national data, we assessed the association between COVID-19 diagnosis and patient outcomes following mechanical thrombectomy. MATERIALS AND METHODS: Patients in this study were identified from the 2020 National Inpatient Sample. All patients with arterial strokes undergoing mechanical thrombectomy were identified using ICD-10 coding criteria. Patients were further stratified by COVID diagnosis (positive vs. negative). Other covariates, including patient/hospital demographics, disease severity, and comorbidities were collected. Multivariable analysis was used to determine the independent effect of COVID-19 on in-hospital mortality and unfavorable discharge. RESULTS: 5078 patients were identified in this study; 166 (3.3%) were COVID-19 positive. COVID-19 patients had a significantly higher mortality rate (30.1% vs. 12.4%, p < 0.001). When controlling for patient/hospital characteristics, APR-DRG disease severity, and Elixhauser Comorbidity Index, COVID-19 was an independent predictor of increased mortality (OR 1.13, p = 0.002). COVID-19 was not significantly related to discharge disposition (p = 0.480). Older age and increased APR-DRG disease severity were also correlated with increase morality. CONCLUSIONS: Overall, this study indicates that COVID-19 is a predictor of mortality among mechanical thrombectomy. This finding is likely multifactorial but may be related to multisystem inflammation, hypercoagulability, and re-occlusion seen in COVID-19 patients. Further research would be needed to clarify these relationships.

Occipital Headache Evaluation and Rates of Migraine Assessment, Diagnosis, and Treatment in Patients Receiving Greater Occipital Nerve Blocks in an Academic Pain Clinic.

OBJECTIVE: Diagnosis of patients with occipital headache can be challenging, as both primary and secondary causes must be considered. Our study assessed how often migraine is screened for, diagnosed, and treated in patients receiving greater occipital nerve blocks (GONBs) in a pain clinic. DESIGN: Institutional review board-approved, retrospective observational study. SETTING: Academic multidisciplinary pain clinic. SUBJECTS: One hundred forty-three consecutive patients who received GONBs. RESULTS: About 75% of patients had been evaluated by neurologists and about 25% by non-neurologist pain specialists only, and 62.2% of patients had photophobia, phonophobia, and nausea assessed. Compared with patients who had been evaluated by non-neurologists, patients who had been evaluated by a neurologist were more likely to have photophobia, phonophobia, and nausea assessed (75.9% vs 20.0%, odds ratio [OR] 12.6, 95% confidence interval [CI] 4.90 to 32.2); more likely to be diagnosed with migraine (48.1% vs 14.3%, OR 5.6, 95% CI 2.0 to 15); less likely to be diagnosed with occipital neuralgia (39.8% vs 65.7%, OR 0.3, 95% CI 0.2 to 0.8); and equally likely to be diagnosed with cervicogenic headache (21.3% vs 25.7%, OR 0.8, 95% CI 0.3 to 1.9). Among patients diagnosed with migraine, 82.5% received acute migraine treatment, 89.5% received preventive migraine treatment, and 52.6% were documented as receiving migraine lifestyle counseling. CONCLUSIONS: Of the patients in this study who had occipital headache and received GONBs, 62.2% were assessed for migraine, and most received appropriate acute, preventive, and lifestyle treatments when diagnosed. Patients seen by neurologists were significantly more likely to be screened for and diagnosed with migraine than were those evaluated by non-neurologist pain medicine specialists only. All clinicians should remain vigilant for migraine in patients with occipital headache.

Patient-Derived In Vitro and In Vivo Models of Cancer.

Over the last two decades, cancer researchers have taken the promise offered by the Human Genome Project and have expanded its capacity to use sequencing to identify the genomic alterations that give rise to and sustain individual tumors. This expansion has allowed researchers to identify and target highly recurrent alterations in specific cancer contexts, such as EGFR mutations in non-small cell lung cancer (Lynch et al, N Engl J Med 350:2129-2139, 2004; Sharifnia et al., Proc Natl Acad Sci U S A 111:18661-18666, 2014), BCR-ABL translocations in chronic myeloid leukemia (Deininger, Pharmacol Rev 55:401-423. https://doi.org/10.1124/pr.55.3.4 , 2003; Druker et al, N Engl J Med 344. 1038-1042, 2001; Druker et al, N Engl J Med 344:1031-1037. https://doi.org/10.1056/NEJM200104053441401 , 2001), or HER2 amplifications in breast cancer (Slamon et al, N Engl J Med 344:783-792. https://doi.org/10.1056/NEJM200103153441101 , 2001; Solca et al, Beyond trastuzumab: second-generation targeted therapies for HER-2-positive breast cancer. In: Sibilia M, Zielinski CC, Bartsch R, Grunt TW (eds) Drugs for HER-2-positive breast cancer. Springer, Basel, pp 91-107, 2011). Despite these advances in our capacity to identify the genetic alterations that drive tumor initiation, survival, and proliferation, our ability to target these alterations to provide effective treatment options for patients in need, particularly those with rare or advanced cancers, remains limited (Gould et al, Nat Med 21:431-439. https://doi.org/10.1038/nm.3853 , 2015). Patient-derived models of cancer offer one potential mechanism to overcome this barrier between the bench and bedside. Through the development and testing of patient-derived models of cancer, functional genomics efforts can identify tumor-specific drug sensitivities and thereby provide a connection between tumor genetics and effective therapeutics for patients in need of treatment options.Recognizing that cancer is a multifaceted set of disease states, the development of personalized models of cancer that can be used to compare treatment options, identify tumor-specific vulnerabilities, and guide clinical decision-making has tremendous potential for improving patient outcomes. This chapter will describe a representative set of patient-derived models of cancer, reviewing each of their strengths and weaknesses and highlighting how selecting a model to suit a specific question or context is critical. Each model comes with a unique set of pros and cons, making them more or less appropriate for each specific research or clinical question. As each model can be leveraged to gain new insights into cancer biology, the key to their deployment is to identify the most appropriate model for a specific context, while carefully considering the strengths and limitations of the selected model. When used appropriately, patient-derived models may prove to be the missing link needed to bring the promise of personalized oncology to fruition in the clinic.

Fenofibrate prevents skeletal muscle loss in mice with lung cancer.

The cancer anorexia cachexia syndrome is a systemic metabolic disorder characterized by the catabolism of stored nutrients in skeletal muscle and adipose tissue that is particularly prevalent in nonsmall cell lung cancer (NSCLC). Loss of skeletal muscle results in functional impairments and increased mortality. The aim of the present study was to characterize the changes in systemic metabolism in a genetically engineered mouse model of NSCLC. We show that a portion of these animals develop loss of skeletal muscle, loss of adipose tissue, and increased inflammatory markers mirroring the human cachexia syndrome. Using noncachexic and fasted animals as controls, we report a unique cachexia metabolite phenotype that includes the loss of peroxisome proliferator-activated receptor-α (PPARα) -dependent ketone production by the liver. In this setting, glucocorticoid levels rise and correlate with skeletal muscle degradation and hepatic markers of gluconeogenesis. Restoring ketone production using the PPARα agonist, fenofibrate, prevents the loss of skeletal muscle mass and body weight. These results demonstrate how targeting hepatic metabolism can prevent muscle wasting in lung cancer, and provide evidence for a therapeutic strategy.

Assessing the spatial distribution of cervical spinal cord activity during tactile stimulation of the upper extremity in humans with functional magnetic resonance imaging.

Dermatomal maps are a mainstay of clinical practice and provide information on the spatial distribution of the cutaneous innervation of spinal nerves. Dermatomal deficits can help isolate the level of spinal nerve root involvement in spinal conditions and guide clinicians in diagnosis and treatment. Dermatomal maps, however, have limitations, and the spatial distribution of spinal cord sensory activity in humans remains to be quantitatively assessed. Here we used spinal cord functional MRI to map and quantitatively compare the spatial distribution of sensory spinal cord activity during tactile stimulation of the left and right lateral shoulders (i.e. C5 dermatome) and dorsal third digits of the hands (i.e., C7 dermatome) in healthy humans (n â€‹= â€‹24, age â€‹= â€‹36.8 â€‹± â€‹11.8 years). Based on the central sites for processing of innocuous tactile sensory information, we hypothesized that the activity would be localized more to the ipsilateral dorsal spinal cord with the lateral shoulder stimulation activity being localized more superiorly than the dorsal third digit. The findings demonstrate lateralization of the activity with the left- and right-sided stimuli having more activation in the ipsilateral hemicord. Contradictory to our hypotheses, the activity for both stimulation sites was spread across the dorsal and ventral hemicords and did not demonstrate a clear superior-inferior localization. Instead, the activity for both stimuli had a broader than expected distribution, extending across the C5, C6, and C7 spinal cord segments. We highlight the complexity of the human spinal cord neuroanatomy and several sources of variability that may explain the observed patterns of activity. While the findings were not completely consistent with our a priori hypotheses, this study provides a foundation for continued work and is an important step towards developing normative quantitative spinal cord measures of sensory function, which may become useful objective MRI-based biomarkers of neurological injury and improve the management of spinal disorders.

Obesity-associated Adipose Stromal Cells Promote Breast Cancer Invasion Through Direct Cell Contact and ECM Remodeling.

Obesity increases the risk and worsens the prognosis for breast cancer due, in part, to altered adipose stromal cell (ASC) behavior. Whether ASCs from obese individuals increase migration of breast cancer cells relative to their lean counterparts, however, remains unclear. To test this connection, multicellular spheroids composed of MCF10A-derived tumor cell lines of varying malignant potential and lean or obese ASCs were embedded into collagen scaffolds mimicking the elastic moduli of interstitial breast adipose tissue. Confocal image analysis suggests that tumor cells alone migrate insignificantly under these conditions. However, direct cell-cell contact with either lean or obese ASCs enables them to migrate collectively, whereby obese ASCs activate tumor cell migration more effectively than their lean counterparts. Time-resolved optical coherence tomography (OCT) imaging suggests that obese ASCs facilitate tumor cell migration by mediating contraction of local collagen fibers. Matrix metalloproteinase (MMP)-dependent proteolytic activity significantly contributes to ASC-mediated tumor cell invasion and collagen deformation. However, ASC contractility is also important, as co-inhibition of both MMPs and contractility is necessary to completely abrogate ASC-mediated tumor cell migration. These findings imply that obesity-mediated changes of ASC phenotype may impact tumor cell migration and invasion with potential implications for breast cancer malignancy in obese patients.

Tuning fullerene miscibility with porphyrin-terminated P3HTs in bulk heterojunction blends.

Understanding and manipulating the miscibility of donor and acceptor components in the active layer morphology is important to optimize the longevity of organic photovoltaic devices and control power conversion efficiency. In pursuit of this goal, a "porphyrin-capped" poly(3-hexylthiophene) was synthesized to take advantage of strong porphyrin:fullerene intermolecular interactions that modify fullerene miscibility in the active layer. End-functionalized poly(3-hexylthiophene) was synthesized via catalyst transfer polymerization and subsequently functionalized with a porphyrin moiety via post-polymerization modification. UV-vis spectroscopy and X-ray diffraction measurements show that the porphyrin-functionalized poly(3-hexylthiophene) exhibits increased intermolecular interactions with phenyl-C61-butyric acid methyl ester (PCBM) in the solid state compared to unfunctionalized poly(3-hexylthiophene) without sacrificing microstructure ordering that facilitates optimal charge transport properties. Additionally, differential scanning calorimetry revealed porphyrin-functionalized poly(3-hexylthiophene) crystallization decreased only slightly (1-6%) compared to unfunctionalized poly(3-hexylthiophenes) while increasing fullerene miscibility by 55%. Preliminary organic photovoltaic device results indicate device power conversion efficiency is sensitive to additive loading levels, as evident by a slight increase in power conversion efficiency at low additive loading levels but a continuous decrease with increased loading levels. While the increased fullerene miscibility is not balanced with significant increases in power conversion efficiency, this approach suggests that integrating non-bonded interaction potentials is a useful pathway for manipulating the morphology of the bulk heterojunction thin film, and porphyrin-functionalized poly(3-hexylthiophenes) may be useful additives in that regard.

Impact of CrossFit-Related Spinal Injuries.

INTRODUCTION: Exercise-related injuries (ERIs) are a common cause of nonfatal emergency department and hospital visits. CrossFit is a high-intensity workout regimen whose popularity has grown rapidly. However, ERIs due to CrossFit remained under investigated. METHODS: All patients who presented to the main hospital at a major academic center complaining of an injury sustained performing CrossFit between June 2010 and June 2016 were identified. Injuries were classified by anatomical location (eg, knee, spine). For patients with spinal injuries, data were collected including age, sex, body mass index (BMI), CrossFit experience level, symptom duration, type of symptoms, type of clinic presentation, cause of injury, objective neurological examination findings, imaging type, number of clinic visits, and treatments prescribed. RESULTS: Four hundred ninety-eight patients with 523 CrossFit-related injuries were identified. Spine injuries were the most common injuries identified, accounting for 20.9%. Among spine injuries, the most common location of injury was the lumbar spine (83.1%). Average symptom duration was 6.4 months ± 15.1, and radicular complaints were the most common symptom (53%). A total of 30 (32%) patients had positive findings on neurologic examination. Six patients (6.7%) required surgical intervention for treatment after failing an average of 9.66 months of conservative treatment. There was no difference in age, sex, BMI, or duration of symptoms of patients requiring surgery with those who did not. CONCLUSIONS: CrossFit is a popular, high-intensity style workout with the potential to injure its participants. Spine injuries were the most common type of injury observed and frequently required surgical intervention.

PTEN function: the long and the short of it.

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a phosphatase that is frequently altered in cancer. PTEN has phosphatase-dependent and -independent roles, and genetic alterations in PTEN lead to deregulation of protein synthesis, the cell cycle, migration, growth, DNA repair, and survival signaling. PTEN localization, stability, conformation, and phosphatase activity are controlled by an array of protein-protein interactions and post-translational modifications. Thus, PTEN-interacting and -modifying proteins have profound effects on the tumor suppressive functions of PTEN. Moreover, recent studies identified mechanisms by which PTEN can exit cells, via either exosomal export or secretion, and act on neighboring cells. This review focuses on modes of PTEN protein regulation and ways in which perturbations in this regulation may lead to disease.

Tailoring Surface Properties through in Situ Functionality Gradients in Reactively Modified Poly(2-vinyl-4,4-dimethyl azlactone) Thin Films.

Generating physical or chemical gradients in thin-film scaffolds is an efficient approach for screening and optimizing an interfacial structure or chemical functionality to create tailored surfaces that are useful because of their wetting, antifouling, or barrier properties. The relationship between the structure of poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) brushes created by the preferential assembly of poly(glycidyl methacrylate)- block-PVDMA diblock copolymers and the ability to chemically modify the PVDMA chains in situ to create a gradient in functionality are examined to investigate how the extent of functionalization affects the interfacial and surface properties. The introduction of a chemical gradient by controlled immersion allows reactive modification to generate position-dependent properties that are assessed by ellipsometry, attenuated total reflectance-Fourier transform infrared spectroscopy, contact angle measurements, and atomic force microscopy imaging. After functionalization of the azlactone rings with n-alkyl amines, ellipsometry confirms an increase in thickness and contact angle measurements support an increase in hydrophobicity along the substrate. These results are used to establish relationships between layer thickness, reaction time, position, and the extent of functionalization and demonstrate that gradual immersion into the functionalizing solution results in a linear change in chemical functionality along the surface. These findings broadly support efforts to produce tailored surfaces by in situ chemical modification, having application as tailored membranes, protein resistant surfaces, or sensors.