Hippo Pathway in Organ Size Control, Tissue Homeostasis, and Cancer.

The Hippo pathway was initially identified in Drosophila melanogaster screens for tissue growth two decades ago and has been a subject extensively studied in both Drosophila and mammals in the last several years. The core of the Hippo pathway consists of a kinase cascade, transcription coactivators, and DNA-binding partners. Recent studies have expanded the Hippo pathway as a complex signaling network with >30 components. This pathway is regulated by intrinsic cell machineries, such as cell-cell contact, cell polarity, and actin cytoskeleton, as well as a wide range of signals, including cellular energy status, mechanical cues, and hormonal signals that act through G-protein-coupled receptors. The major functions of the Hippo pathway have been defined to restrict tissue growth in adults and modulate cell proliferation, differentiation, and migration in developing organs. Furthermore, dysregulation of the Hippo pathway leads to aberrant cell growth and neoplasia. In this review, we focus on recent developments in our understanding of the molecular actions of the core Hippo kinase cascade and discuss key open questions in the regulation and function of the Hippo pathway.

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Mechanisms of Hippo pathway regulation

A growing body of evidence suggests that mechanical signals emanating from the cell's microenvironment are fundamental regulators of cell behaviour. Moreover, at the macroscopic scale, the influence of forces, such as the forces generated by blood flow, muscle contraction, gravity and overall tissue rigidity (for example, inside of a tumour lump), is central to our understanding of physiology and disease pathogenesis. Still, how mechanical cues are sensed and transduced at the molecular level to regulate gene expression has long remained enigmatic. The identification of the transcription factors YAP and TAZ as mechanotransducers started to fill this gap. YAP and TAZ read a broad range of mechanical cues, from shear stress to cell shape and extracellular matrix rigidity, and translate them into cell-specific transcriptional programmes. YAP and TAZ mechanotransduction is critical for driving stem cell behaviour and regeneration, and it sheds new light on the mechanisms by which aberrant cell mechanics is instrumental for the onset of multiple diseases, such as atherosclerosis, fibrosis, pulmonary hypertension, inflammation, muscular dystrophy and cancer.

Mechanobiology of YAP and TAZ in physiology and disease

https://www.cell.com/trends/cell-biology/pdf/S0962-8924(15)00086-0.pdf

YAP and TAZ: a nexus for Hippo signaling and beyond.

Summary Background Dual blockade of the EGFR and VEGF pathways in EGFR-mutated metastatic non-small-cell lung cancer (NSCLC) is supported by preclinical and clinical data, yet the approach is not widely implemented. RELAY assessed erlotinib, an EGFR tyrosine kinase inhibitor (TKI) standard of care, plus ramucirumab, a human IgG1 VEGFR2 antagonist, or placebo in patients with untreated EGFR-mutated metastatic NSCLC. Methods This is a worldwide, double-blind, phase 3 trial done in 100 hospitals, clinics, and medical centres in 13 countries. Eligible patients were aged 18 years or older (20 years or older in Japan and Taiwan) at the time of study entry, had stage IV NSCLC, with an EGFR exon 19 deletion (ex19del) or exon 21 substitution (Leu858Arg) mutation, an Eastern Cooperative Oncology Group performance status of 0 or 1, and no CNS metastases. We randomly assigned eligible patients in a 1:1 ratio to receive oral erlotinib (150 mg/day) plus either intravenous ramucirumab (10 mg/kg) or matching placebo once every 2 weeks. Randomisation was done by an interactive web response system with a computer-generated sequence and stratified by sex, geographical region, EGFR mutation type, and EGFR testing method. The primary endpoint was investigator-assessed progression-free survival in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study treatment. This trial is registered at ClinicalTrials.gov, NCT02411448, and is ongoing for long-term survival follow-up. Findings Between Jan 28, 2016, and Feb 1, 2018, 449 eligible patients were enrolled and randomly assigned to treatment with ramucirumab plus erlotinib (n=224) or placebo plus erlotinib (n=225). Median duration of follow-up was 20·7 months (IQR 15·8–27·2). At the time of primary analysis, progression-free survival was significantly longer in the ramucirumab plus erlotinib group (19·4 months [95% CI 15·4–21·6]) than in the placebo plus erlotinib group (12·4 months [11·0–13·5]), with a stratified hazard ratio of 0·59 (95% CI 0·46–0·76; p Interpretation Ramucirumab plus erlotinib demonstrated superior progression-free survival compared with placebo plus erlotinib in patients with untreated EGFR-mutated metastatic NSCLC. Safety was consistent with the safety profiles of the individual compounds in advanced lung cancer. The RELAY regimen is a viable new treatment option for the initial treatment of EGFR-mutated metastatic NSCLC. Funding Eli Lilly.

https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(19)30634-5.pdf

Ramucirumab plus erlotinib in patients with untreated, EGFR-mutated, advanced non-small-cell lung cancer (RELAY): a randomised, double-blind, placebo-controlled, phase 3 trial.

Shear stress activates cellular signaling involved in cellular proliferation, differentiation, and migration. However, the mechanisms of mesenchymal stem cell (MSC) differentiation under interstitial flow are not fully understood. Here, we show the increased osteogenic differentiation of MSCs under exposure to constant, extremely low shear stress created by osmotic pressure-induced flow in a microfluidic chip. The interstitial level of shear stress in the proposed microfluidic system stimulated nuclear localization of TAZ (transcriptional coactivator with PDZ-binding motif), a transcriptional modulator of MSCs, activated TAZ target genes such as CTGF and Cyr61, and induced osteogenic differentiation. TAZ-depleted cells showed defects in shear stress-induced osteogenic differentiation. In shear stress induced cellular signaling, Rho signaling pathway was important forthe nuclear localization of TAZ. Taken together, these results suggest that TAZ is an important mediator of interstitial flow-driven shear stress signaling in osteoblast differentiation of MSCs.

https://dspace.ewha.ac.kr/bitstream/2015.oak/227632/1/001.pdf

Shear stress induced by an interstitial level of slow flow increases the osteogenic differentiation of mesenchymal stem cells through TAZ activation.

Size-controllable networked neurospheres as a 3D neuronal tissue model for Alzheimer's disease studies.

Alzheimer's disease is accompanied by progressive, time-dependent changes of three moieties of amyloid beta. In vitro models therefore should provide same conditions for more physiologic studies. Here we observed changes in the number of fibrils over time and studied the correlation between amyloid beta moieties and neurotoxicity. Although the number of fibrils increased dramatically, the change in neurotoxicity with time was small, suggesting that fibrils make little contribution to neurotoxicity. To study the neurotoxicity of diffusible moieties by regulating microenvironments, we created a bio-mimetic microfluidic system generating spatial gradients of diffusible oligomeric assemblies and assessed their effects on cultured neurons. We found amyloid beta exposure produced an atrophy effect and observed neurite extension during the differentiation of neural progenitor cells increased when cells were cultured with continuous flow. The results demonstrate the potential neurotoxicity of oligomeric assemblies and establish a prospective microfluidic platform for studying the neurotoxicity of amyloid beta.

/pdf/neurotoxic-amyloid-beta-oligomeric-assemblies-recreated-in-rdfziqmplr.pdf

Neurotoxic amyloid beta oligomeric assemblies recreated in microfluidic platform with interstitial level of slow flow.

n engl j med 378;13 nejm.org March 29, 2018 1261 3. Opotowsky AR, Moko LE, Ginns J, et al. Pheochromocytoma and paraganglioma in cyanotic congenital heart disease. J Clin Endocrinol Metab 2015; 100: 1325-34. 4. Zhuang Z, Yang C, Lorenzo F, et al. Somatic HIF2A gain-offunction mutations in paraganglioma with polycythemia. N Engl J Med 2012; 367: 922-30. 5. Toledo RA, Qin Y, Srikantan S, et al. In vivo and in vitro oncogenic effects of HIF2A mutations in pheochromocytomas and paragangliomas. Endocr Relat Cancer 2013; 20: 34959.

Osimertinib in EGFR Mutation-Positive Advanced NSCLC.

Background:Genetic and behavioral risk factors have been suggested to play a role in anterior cruciate ligament (ACL) injury. However, population-based familial risk estimates are unavailable.Purpo...

Familial Risk and Its Interaction With Body Mass Index and Physical Activity in Anterior Cruciate Ligament Injury Among First-Degree Relatives: A Population-Based Cohort Study:

Yoon Jung Choi

Papers

Shear stress induced by an interstitial level of slow flow increases the osteogenic differentiation of mesenchymal stem cells through TAZ activation.

Size-controllable networked neurospheres as a 3D neuronal tissue model for Alzheimer's disease studies.

Neurotoxic amyloid beta oligomeric assemblies recreated in microfluidic platform with interstitial level of slow flow.

Osimertinib in EGFR Mutation-Positive Advanced NSCLC.

Familial Risk and Its Interaction With Body Mass Index and Physical Activity in Anterior Cruciate Ligament Injury Among First-Degree Relatives: A Population-Based Cohort Study: