Mechanotransduction of mitochondrial AMPK and its distinct role in flow-induced breast cancer cell migration

The biophysical microenvironment of the tumor site has significant impact on breast cancer progression and metastasis. The importance of altered mechanotransduction in cancerous tissue has been documented, yet its role in the regulation of cellular metabolism and the potential link between cellular energy and cell migration remain poorly understood. In this study, we investigated the role of mechanotransduction in AMP-activated protein kinase (AMPK) activation in breast cancer cells in response to interstitial fluid flow (IFF). Additionally, we explored the involvement of AMPK in breast cancer cell migration. IFF was applied to the 3D cell-matrix construct. The subcellular signaling activity of Src, FAK, and AMPK was visualized in real-time using fluorescent resonance energy transfer (FRET). We observed that breast cancer cells (MDA-MB-231) are more sensitive to IFF than normal epithelial cells (MCF-10A). AMPK was activated at the mitochondria of MDA-MB-231 cells by IFF, but not in other subcellular compartments (i.e., cytosol, plasma membrane, and nucleus). The inhibition of FAK or Src abolished flow-induced AMPK activation in the mitochondria of MDA-MB-231 cells. We also observed that global AMPK activation reduced MDA-MB-231 cell migration. Interestingly, specific AMPK inhibition in the mitochondria reduced cell migration and blocked flow-induced cell migration. Our results suggest the linkage of FAK/Src and mitochondria-specific AMPK in mechanotransduction and the differential role of AMPK in breast cancer cell migration depending on its subcellular compartment-specific activation

Spinal Implant Design and Subsidence

A spinal implant may be used in people who have diseased or injured intervertebral discs pushing against their spinal cord and nerves, causing them loss of sensation due to nerve impingement. Patients who have not found relief through non-surgical means may require a discectomy, which removes the disc and relieves the pressure. There are several ways to then fill the resulting gap which include fusion devices, artificial disc replacement (ADR) devices, or bone grafts. Our study focused on the first two mechanical options. Subsidence, or the vertical movement of the device into the adjacent vertebral bodies, is an often reported mechanical adverse event for current FDA-approved devices. Our goal was to find how geometric parameters influence subsidence of spinal fusion and ADR devices. Following ASTM F2267, we tested devices which held specific geometric parameters constant while varying others. Several conclusions resulted from these tests, drawn from an understanding of load-displacement curves. It was found that devices with a larger contact area subside less and that subsidence is not a function of sagittal profile, but rather of contact area between vertebral endplates and the intervertebral device. With respect to ADR devices with fins, subsidence is a function of how much bone is removed. For these implants with rectangular extruded fins, volume is the primary indicator of subsidence over fin number and length. Similar experiments were conducted with paired porcine vertebrae in order to support the conclusions drawn from ASTM F2267 testing and provide an in vitro study of subsidence. With this in vitro study, additional conclusions include the use of fins for stability and the importance of the decortication and rasping surgical procedures. The results of these tests provide an understanding of how specific geometric parameters can be varied to reduce subsidence of intervertebral disc replacement devices in the spine

Fluid flow-induced activation of subcellular AMPK and its interaction with FAK and Src

AMP-activated protein kinase (AMPK) is a metabolic energy sensor that plays a critical role in cancer cell survival and growth. While the physical microenvironment is believed to influence tumor growth and progression, its role in AMPK regulation remains largely unknown. In the present study, we evaluated AMPK response to mechanical forces and its interaction with other mechano-responsive signaling proteins, FAK and Src. Using genetically encoded biosensors that can detect AMPK activities at different subcellular locations (cytosol, plasma membrane, nucleus, mitochondria, and Golgi apparatus), we observed that AMPK responds to shear stress in a subcellular location-dependent manner in breast cancer cells (MDA-MB-231). While normal epithelial cells (MCF-10A) also similarly responded to shear stress, they are less sensitive to shear stress compared to MDA-MB-231 cells. Inhibition of FAK and Src significantly decreased the basal activity level of AMPK at all five subcellular locations in MDA-MB-231 cells and selectively blocked shear stress-induced AMPK activation. Moreover, testing with cytoskeletal drugs revealed that myosin II might be the critical mediator of shear stress-induced AMPK activation in MDA-MB-231 cells. These findings suggest that breast cancer cells and normal epithelial cells may have different mechanosensitivity in AMPK signaling and that FAK and Src as well as the myosin II-dependent signaling pathway are involved in subcellular AMPK mechanotransduction in breast cancer cells

Cardiac involvement in hereditary myopathy with early respiratory failure: A cohort study.

OBJECTIVE: To assess whether hereditary myopathy with early respiratory failure (HMERF) due to the c.951434T>C; (p.Cys31712Arg) TTN missense mutation also includes a cardiac phenotype. METHOD: Clinical cohort study of our HMERF cohort using ECG, 2D echocardiogram, and cross-sectional cardiac imaging with MRI or CT. RESULTS: We studied 22 participants with the c.951434T>C; (p.Cys31712Arg) TTN missense mutation. Three were deceased. Cardiac conduction abnormalities were identified in 7/22 (32%): sustained atrioventricular tachycardia (n = 2), atrial fibrillation (n = 2), nonsustained atrial tachycardia (n = 1), premature supraventricular complexes (n = 1), and unexplained sinus bradycardia (n = 1). In addition, 4/22 (18%) had imaging evidence of otherwise unexplained cardiomyopathy. These findings are supported by histopathologic correlation suggestive of myocardial cytoskeletal remodeling. CONCLUSIONS: Coexisting cardiac and skeletal muscle involvement is not uncommon in patients with HMERF arising due to the c.951434T>C; (p.Cys31712Arg) TTN mutation. All patients with pathogenic or putative pathogenic TTN mutations should be offered periodic cardiac surveillance.Wellcome Trust (101876/Z/13/Z, 096919Z/11/Z), Medical Research Council (UK) (G0601943), Medical Research Council Mitochondrial Biology Unit (MC_UP_1501/2).This is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1212/WNL.000000000000306

A key role for peroxynitrite-mediated inhibition of cardiac ERG (Kv11.1) K+ channels in carbon monoxide–induced proarrhythmic early afterdepolarizations

Exposure to carbon monoxide (CO) causes early afterdepolarization arrhythmias. Previous studies in rats indicated arrhythmias arose due to augmentation of the late Na+ current. The purpose of the present study was to examine the basis of CO-induced arrhythmias in guinea pig myocytes in which action potentials more closely resemble those of human myocytes. Whole-cell current- and voltage-clamp recordings were made from isolated guinea pig myocytes and also from HEK293 cells expressing wild-type or a C723S mutant form of Kv11.1 (ERG). We also monitored formation of peroxynitrite (ONOO-) in HEK293 cells fluorimetrically. CO, applied as the CO releasing molecule, CORM-2, prolonged action potentials and induced early after-depolarizations (EADs) in guinea pig myocytes. In HEK293 cells CO inhibited wild-type but not C723S mutant Kv11.1 K+ currents. Inhibition was prevented by an antioxidant, mitochondrial inhibitors or inhibition of nitric oxide formation. CO also raised ONOO- levels, an effect reversed by the ONOO- scavenger, FeTPPS which also prevented CO inhibition of Kv11.1 currents, and abolished the effects of CO on Kv11.1 tail currents and action potentials in guinea pig myocytes. Our data suggest that CO induces arrhythmias in guinea pig cardiac myocytes via ONOO--mediated inhibition of Kv11.1 K+ channel

Construction kits or virtual worlds; management applications of E2E models

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 109/110 (2013): 103-108, doi:10.1016/j.jmarsys.2011.10.016.We review briefly the diversity of modeling activity that comes under the rubric of end-to-end (E2E) models, but the focus of this paper – of joint concern to researchers and to managers - is on applications to management and decision making. The models and applications span a range from “construction kits” that identify particular management issues and use comparisons across ecosystems; to “virtual worlds” that immerse managers in the details of strategic evaluations for particular systems. The general conclusion is that “application” is not a straightforward transition from theory to practice but a complex interactive process.This review is based on the proceedings of a workshop, held at Woods Hole Oceanographic Institution, 19-22 April 2010, as part of CAMEO (Comparative Analysis of Marine Ecosystem Organization), a program supported jointly by NOAA (U.S. National Oceanic and Atmospheric Agency) and NSF (U.S. National Science Foundation)

Geospatial analysis of California strawberry fields reveals regional differences in crop rotation patterns and the potential for lengthened rotations at current levels of production

Strawberries in California are grown in specific coastal areas where land is scarce and climate change threatens future production. Strawberry growers are under pressure to adopt sustainable production strategies such as crop rotation, but this practice requires more land than back-to-back planting. The objectives of this research were to quantify the rate of crop rotation across the three main strawberry producing regions in California (Ventura, Santa Maria, and Monterey Bay), and evaluate geographic and edaphic influences on crop rotation. All strawberry fields in the main strawberry producing regions of California were identified by satellite imagery and manual inspection for the years 2017 through 2022. ArcGIS Pro was used to outline each strawberry field and compare among years to determine the period between successive strawberry plantings. Edaphic characteristics and shapefiles for surrounding fields were retrieved from public datasets. The three regions significantly differed in their rates of crop rotation. On average, 95, 52, and 25% of strawberry hectares were rotated each year in the Monterey Bay, Santa Maria, and Ventura regions, respectively. Shorter rotation lengths were associated with reduced distance from the ocean and soil with a higher percentage of sand. Based on 2 years of disease surveys, fields infested with Macrophomina phaseolina tended to be further inland than fields infested with Fusarium oxysporum f. sp. fragariae in the Monterey Bay region. This study determined that distance from the ocean and soil texture are associated with crop rotation lengths in California strawberry production. Enough land may be available in the Santa Maria and Monterey Bay regions for growers to lengthen crop rotations, but water quality, social networks, and financial considerations that were outside the scope of this study are likely to limit the ability for strawberry growers to maximize the duration of crop rotations

Sulfur-bearing phases detected by evolved gas analysis of the Rocknest aeolian deposit, Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument suite detected SO_2, H_(2)S, OCS, and CS_2 from ~450 to 800°C during evolved gas analysis (EGA) of materials from the Rocknest aeolian deposit in Gale Crater, Mars. This was the first detection of evolved sulfur species from a Martian surface sample during in situ EGA. SO_2 (~3–22 µmol) is consistent with the thermal decomposition of Fe sulfates or Ca sulfites, or evolution/desorption from sulfur-bearing amorphous phases. Reactions between reduced sulfur phases such as sulfides and evolved O_2 or H_(2)O in the SAM oven are another candidate SO_2 source. H_(2)S (~41–109 nmol) is consistent with interactions of H_(2)O, H_2 and/or HCl with reduced sulfur phases and/or SO2 in the SAM oven. OCS (~1–5 nmol) and CS2 (~0.2–1 nmol) are likely derived from reactions between carbon-bearing compounds and reduced sulfur. Sulfates and sulfites indicate some aqueous interactions, although not necessarily at the Rocknest site; Fe sulfates imply interaction with acid solutions whereas Ca sulfites can form from acidic to near-neutral solutions. Sulfides in the Rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source. The presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering. The possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage. Understanding the sulfur mineralogy in Rocknest materials, which exhibit chemical similarities to basaltic fines analyzed elsewhere on Mars, can provide insight in to the origin and alteration history of Martian surface materials

Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts