Control of YAP/TAZ Activity by Metabolic and Nutrient-Sensing Pathways

Dihydroartemisinin breaks the positive feedback loop of YAP1 and GLUT1-mediated aerobic glycolysis to boost the CD8+ effector T cells in hepatocellular carcinoma

Aerobic glycolysis is a hallmark of hepatocellular carcinoma (HCC). Dihydroartemisinin (DHA) exhibits antitumor activity towards liver cancer. Our previous studies have shown that DHA inhibits the Warburg effect in HCC cells. However, the mechanism still needs to be clarified. Our study aimed to elucidate the interaction between YAP1 and GLUT1-mediated aerobic glycolysis in HCC cells and focused on the underlying mechanisms of DHA inhibiting aerobic glycolysis in HCC cells. In this study, we confirmed that inhibition of YAP1 expression lowers GLUT1-mediated aerobic glycolysis in HCC cells and enhances the activity of CD8+T cells in the tumor niche. Then, we found that DHA was bound to cellular YAP1 in HCC cells. YAP1 knockdown inhibited GLUT1-mediated aerobic glycolysis, whereas YAP1 overexpression promoted GLUT1-mediated aerobic glycolysis in HCC cells. Notably, liver-specific Yap1 knockout by AAV8-TBG-Cre suppressed HIF-1α and GLUT1 expression in tumors but not para-tumors in DEN/TCPOBOP-induced HCC mice. Even more crucial is that YAP1 forms a positive feedback loop with GLUT1-mediated aerobic glycolysis, which is associated with HIF-1α in HCC cells. Finally, DHA reduced GLUT1-aerobic glycolysis in HCC cells through YAP1 and prevented the binding of YAP1 and HIF-1α. Collectively, our study revealed the mechanism of DHA inhibiting glycolysis in HCC cells from a perspective of a positive feedback loop involving YAP1 and GLUT1 mediated-aerobic glycolysis and provided a feasible therapeutic strategy for targeting enhanced aerobic glycolysis in HCC.

The Prognostic Biomarker RAB7A Promotes Growth and Metastasis of Liver Cancer Cells by Regulating Glycolysis and YAP1 Activation

Activating transcription factor 6 (ATF6) and its downstream genes are involved in progression of hepatocellular carcinoma (HCC). Herein, we demonstrated that sulfhydration of Ras-related protein Rab-7a (RAB7A) was regulated by ATF6. High expression of RAB7A indicated poor prognosis of HCC patients. RAB7A overexpression contributed to proliferation, colony formation, migration, and invasion of HepG2 and Hep3B cells. Furthermore, we found that RAB7A enhanced aerobic glycolysis in HepG2 cells, indicating a higher degree of tumor malignancy. Mechanistically, RAB7A suppressed Yes-associated protein 1 (YAP1) binding to 14-3-3 and conduced to YAP1 nuclear translocation and activation, promoting its downstream gene expression, thereby promoting growth and metastasis of liver cancer cells. In addition, knocking down RAB7A attenuated the progression of orthotopic liver tumors in mice. These findings illustrate the important role of RAB7A in regulating HCC progression. Thus, RAB7A may be a potential innovative target for HCC treatment.

Extracellular matrix stiffness as an energy metabolism regulator drives osteogenic differentiation in mesenchymal stem cells

The biophysical factors of biomaterials such as their stiffness regulate stem cell differentiation. Energy metabolism has been revealed an essential role in stem cell lineage commitment. However, whether and how extracellular matrix (ECM) stiffness regulates energy metabolism to determine stem cell differentiation is less known. Here, the study reveals that stiff ECM promotes glycolysis, oxidative phosphorylation, and enhances antioxidant defense system during osteogenic differentiation in MSCs. Stiff ECM increases mitochondrial fusion by enhancing mitofusin 1 and 2 expression and inhibiting the dynamin-related protein 1 activity, which contributes to osteogenesis. Yes-associated protein (YAP) impacts glycolysis, glutamine metabolism, mitochondrial dynamics, and mitochondrial biosynthesis to regulate stiffness-mediated osteogenic differentiation. Furthermore, glycolysis in turn regulates YAP activity through the cytoskeletal tension-mediated deformation of nuclei. Overall, our findings suggest that YAP is an important mechanotransducer to integrate ECM mechanical cues and energy metabolic signaling to affect the fate of MSCs. This offers valuable guidance to improve the scaffold design for bone tissue engineering constructs.

APIP regulated by YAP propels methionine cycle and metastasis in head and neck squamous cell carcinoma

The Yes-associated protein (YAP) plays a vital role in tumor progression and metabolic regulation. However, the involvement of YAP in metabolic reprogramming of head and neck squamous cell carcinoma remains unclear. Using RNA sequencing and ultra-high-performance liquid chromatography-tandem mass spectrometry, we observed that YAP increased the levels of the main metabolites and enzymes involved in methionine metabolism. APIP, an enzyme involved in the methionine salvage pathway, was transcriptionally activated by YAP. Further experiments showed that APIP promotes HNSCC cells migration and invasion in vitro and tumor metastasis in adjacent lymph nodes and distant organs in vivo. APIP also increases the levels of metabolites in the methionine cycle. We further found that methionine reversed the inhibition of HNSCC migration and invasion by APIP knockdown. In vivo experiments demonstrated that methionine addition promoted tumor metastasis. Mechanistically, the methionine cycle phosphorylated and inactivated GSK3β, then induced the epithelial mesenchymal transition pathway. Increased APIP expression was detected in patients with HNSCC, especially in tumors with lymph node metastasis. Metabolites of methionine cycle were also elevated in HNSCC patients. Our findings revealed that APIP, a novel target of YAP, promotes the methionine cycle and HNSCC metastasis through GSK3β phosphorylation.

Targeting YAP1 to improve the efficacy of immune checkpoint inhibitors in liver cancer: mechanism and strategy

Liver cancer is the third leading of tumor death, including hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Immune checkpoint inhibitors (ICIs) are yielding much for sufferers to hope for patients, but only some patients with advanced liver tumor respond. Recent research showed that tumor microenvironment (TME) is critical for the effectiveness of ICIs in advanced liver tumor. Meanwhile, metabolic reprogramming of liver tumor leads to immunosuppression in TME. These suggest that regulating the abnormal metabolism of liver tumor cells and firing up TME to turn "cold tumor" into "hot tumor" are potential strategies to improve the therapeutic effect of ICIs in liver tumor. Previous studies have found that YAP1 is a potential target to improve the efficacy of anti-PD-1 in HCC. Here, we review that YAP1 promotes immunosuppression of TME, mainly due to the overstimulation of cytokines in TME by YAP1. Subsequently, we studied the effects of YAP1 on metabolic reprogramming in liver tumor cells, including glycolysis, gluconeogenesis, lipid metabolism, arachidonic acid metabolism, and amino acid metabolism. Lastly, we summarized the existing drugs targeting YAP1 in the treatment of liver tumor, including some medicines from natural sources, which have the potential to improve the efficacy of ICIs in the treatment of liver tumor. This review contributed to the application of targeted YAP1 for combined therapy with ICIs in liver tumor patients.

Signaling pathways and targeted therapeutic strategies for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age. Although promising strides have been made in the field of PCOS over the past decades, the distinct etiologies of this syndrome are not fully elucidated. Prenatal factors, genetic variation, epigenetic mechanisms, unhealthy lifestyles, and environmental toxins all contribute to the development of this intricate and highly heterogeneous metabolic, endocrine, reproductive, and psychological disorder. Moreover, interactions between androgen excess, insulin resistance, disruption to the hypothalamic-pituitary-ovary (HPO) axis, and obesity only make for a more complex picture. In this review, we investigate and summarize the related molecular mechanisms underlying PCOS pathogenesis from the perspective of the level of signaling pathways, including PI3K/Akt, TGF-β/Smads, Wnt/β-catenin, and Hippo/YAP. Additionally, this review provides an overview of prospective therapies, such as exosome therapy, gene therapy, and drugs based on traditional Chinese medicine (TCM) and natural compounds. By targeting these aberrant pathways, these interventions primarily alleviate inflammation, insulin resistance, androgen excess, and ovarian fibrosis, which are typical symptoms of PCOS. Overall, we hope that this paper will pave the way for better understanding and management of PCOS in the future.

Nuclear Import and Export of YAP and TAZ

Yes-associated Protein (YAP) and its paralog Transcriptional Coactivator with PDZ-binding Motif (TAZ) are major regulators of gene transcription/expression, primarily controlled by the Hippo pathway and the cytoskeleton. Integrating an array of chemical and mechanical signals, they impact growth, differentiation, and regeneration. Accordingly, they also play key roles in tumorigenesis and metastasis formation. Their activity is primarily regulated by their localization, that is, Hippo pathway- and/or cytoskeleton-controlled cytosolic or nuclear sequestration. While many details of such prevailing retention models have been elucidated, much less is known about their actual nuclear traffic: import and export. Although their size is not far from the cutoff for passive diffusion through the nuclear pore complex (NPC), and they do not contain any classic nuclear localization (NLS) or nuclear export signal (NES), evidence has been accumulating that their shuttling involves mediated and thus regulatable/targetable processes. The aim of this review is to summarize emerging information/concepts about their nucleocytoplasmic shuttling, encompassing the relevant structural requirements (NLS, NES), nuclear transport receptors (NTRs, karyophererins), and NPC components, along with the potential transport mechanisms and their regulation. While dissecting retention vs. transport is often challenging, the emerging picture suggests that YAP/TAZ shuttles across the NPC via multiple, non-exclusive, mediated mechanisms, constituting a novel and intriguing facet of YAP/TAZ biology.

Role of the YAP/TAZ-TEAD Transcriptional Complex in the Metabolic Control of TRAIL Sensitivity by the Mevalonate Pathway in Cancer Cells

Different studies have reported that inhibiting the mevalonate pathway with statins may increase the sensitivity of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), although the signaling mechanism leading to this sensitization remains largely unknown. We investigated the role of the YAP (Yes-associated protein)/TAZ (transcriptional co-activator with PDZ-binding motif)-TEAD (TEA/ATTS domain) transcriptional complex in the metabolic control of TRAIL sensitivity by the mevalonate pathway. We show that depleting nuclear YAP/TAZ in tumor cells, either via treatment with statins or by silencing YAP/TAZ expression with siRNAs, facilitates the activation of apoptosis by TRAIL. Furthermore, the blockage of TEAD transcriptional activity either pharmacologically or through the ectopic expression of a disruptor of the YAP/TAZ interaction with TEAD transcription factors, overcomes the resistance of tumor cells to the induction of apoptosis by TRAIL. Our results show that the mevalonate pathway controls cellular the FLICE-inhibitory protein (cFLIP) expression in tumor cells. Importantly, inhibiting the YAP/TAZ-TEAD signaling pathway induces cFLIP down-regulation, leading to a marked sensitization of tumor cells to apoptosis induction by TRAIL. Our data suggest that a combined strategy of targeting TEAD activity and selectively activating apoptosis signaling by agonists of apoptotic TRAIL receptors could be explored as a potential therapeutic approach in cancer treatment.

AR activates YAP/TAZ differentially in prostate cancer

The Hippo signalling pathway is a master regulator of cell growth, proliferation, and cancer. The transcriptional coregulators of the Hippo pathway, YAP and TAZ, are central in various cancers. However, how YAP and TAZ get activated in most types of cancers is not well understood. Here, we show that androgens activate YAP/TAZ via the androgen receptor (AR) in prostate cancer (PCa), and that this activation is differential. AR regulates YAP translation while inducing transcription of the TAZ encoding gene, WWTR1 Furthermore, we show that AR-mediated YAP/TAZ activation is regulated by the RhoA GTPases transcriptional mediator, serum response factor (SRF). Importantly, in prostate cancer patients, SRF expression positively correlates with TAZ and the YAP/TAZ target genes CYR61 and CTGF We demonstrate that YAP/TAZ are not essential for sustaining AR activity, however, targeting YAP/TAZ or SRF sensitize PCa cells to AR inhibition in anchorage-independent growth conditions. Our findings dissect the cellular roles of YAP, TAZ, and SRF in prostate cancer cells. Our data emphasize the interplay between these transcriptional regulators and their roles in prostate tumorigenesis and highlight how these insights might be exploited therapeutically.

Positive feedback loops between fibroblasts and the mechanical environment contribute to dermal fibrosis

Dermal fibrosis is characterized by excessive deposition of extracellular matrix in the dermis and affects millions of people worldwide and causes limited movement, disfigurement and psychological distress in patients. Fibroblast dysfunction of plays a central role in the pathogenesis of dermal fibrosis and is controlled by distinct factors. Recent studies support the hypothesis that fibroblasts can drive matrix deposition and stiffening, which in turn can exacerbate the functional dysregulation of fibroblasts. Ultimately, through a positive feedback loop, uncontrolled pathological fibrosis develops. This review aims to summarize the phenomenon and mechanism of the positive feedback loop in dermal fibrosis, and discuss potential therapeutic targets to help further elucidate the pathogenesis of dermal fibrosis and develop therapeutic strategies. In this review, fibroblast-derived compositional and structural changes in the ECM that lead to altered mechanical properties are briefly discussed. We focus on the mechanisms by which mechanical cues participate in dermal fibrosis progression. The mechanosensors discussed in the review include integrins, DDRs, proteoglycans, and mechanosensitive ion channels. The FAK, ERK, Akt, and Rho pathways, as well as transcription factors, including MRTF and YAP/TAZ, are also discussed. In addition, we describe stiffness-induced biological changes in the ECM on fibroblasts that contribute to the formation of a positive feedback loop. Finally, we discuss therapeutic strategies to treat the vicious cycle and present important suggestions for researchers conducting in-depth research.

The genetic landscape and possible therapeutics of neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a genetic condition marked by the development of multiple benign tumors in the nervous system. The most common tumors associated with NF2 are bilateral vestibular schwannoma, meningioma, and ependymoma. The clinical manifestations of NF2 depend on the site of involvement. Vestibular schwannoma can present with hearing loss, dizziness, and tinnitus, while spinal tumor leads to debilitating pain, muscle weakness, or paresthesias. Clinical diagnosis of NF2 is based on the Manchester criteria, which have been updated in the last decade. NF2 is caused by loss-of-function mutations in the NF2 gene on chromosome 22, leading the merlin protein to malfunction. Over half of NF2 patients have de novo mutations, and half of this group are mosaic. NF2 can be managed by surgery, stereotactic radiosurgery, monoclonal antibody bevacizumab, and close observation. However, the nature of multiple tumors and the necessity of multiple surgeries over the lifetime, inoperable tumors like meningiomatosis with infiltration of the sinus or in the area of the lower cranial nerves, the complications caused by the operation, the malignancies induced by radiotherapy, and inefficiency of cytotoxic chemotherapy due to the benign nature of NF-related tumors have led a march toward exploring targeted therapies. Recent advances in genetics and molecular biology have allowed identifying and targeting of underlying pathways in the pathogenesis of NF2. In this review, we explain the clinicopathological characteristics of NF2, its genetic and molecular background, and the current knowledge and challenges of implementing genetics to develop efficient therapies.

Lipophilic Statins Inhibit YAP Nuclear Localization, Coactivator Activity, and Migration in Response to Ligation of HLA Class I Molecules in Endothelial Cells: Role of YAP Multisite Phosphorylation

Solid-organ transplant recipients exhibiting HLA donor-specific Abs are at risk for graft loss due to chronic Ab-mediated rejection. HLA Abs bind HLA molecules expressed on the surface of endothelial cells (ECs) and induce intracellular signaling pathways, including the activation of the transcriptional coactivator yes-associated protein (YAP). In this study, we examined the impact of lipid-lowering drugs of the statin family on YAP localization, multisite phosphorylation, and transcriptional activity in human ECs. Exposure of sparse cultures of ECs to cerivastatin or simvastatin induced striking relocalization of YAP from the nucleus to the cytoplasm and inhibited the expression of the YAP/TEA domain DNA-binding transcription factor-regulated genes connective tissue growth factor and cysteine-rich angiogenic inducer 61. In dense cultures of ECs, statins prevented YAP nuclear import and expression of connective tissue growth factor and cysteine-rich angiogenic inducer 61 stimulated by the mAb W6/32 that binds HLA class I. Exposure of ECs to either cerivastatin or simvastatin completely blocked the migration of ECs stimulated by ligation of HLA class I. Exogenously supplied mevalonic acid or geranylgeraniol reversed the inhibitory effects of statins on YAP localization either in low-density ECs or high-density ECs challenged with W6/32. Mechanistically, cerivastatin increased the phosphorylation of YAP at Ser127, blunted the assembly of actin stress fiber, and inhibited YAP phosphorylation at Tyr357 in ECs. Using mutant YAP, we substantiated that YAP phosphorylation at Tyr357 is critical for YAP activation. Collectively, our results indicate that statins restrain YAP activity in EC models, thus providing a plausible mechanism underlying their beneficial effects in solid-organ transplant recipients.

TPM2 attenuates progression of prostate cancer by blocking PDLIM7-mediated nuclear translocation of YAP1

BACKGROUND

Prostate cancer (PCa) is a common malignant tumor of the genitourinary system. Clinical intervention in advanced PCa remains challenging. Tropomyosins 2 (TPM2) are actin-binding proteins and have been found as a biomarker candidate for certain cancers. However, no studies have explored the role of TPM2 in PCa and its regulatory mechanism.

METHODS

TPM2 expression was assessed in Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) PCa patient dataset. The effect of TPM2 on PCa progression was assessed in vitro and in vivo by quantifying proliferation, migration, invasion and tumor growth assays, and the mechanism of TPM2 in PCa progression was gradually revealed by Western blotting, immunoprecipitation, and immunofluorescence staining arrays.

RESULTS

TPM2 was found to be severely downregulated in tumor tissues of PCa patients compared with tumor-adjacent normal tissues. In vitro experiments revealed that TPM2 overexpression inhibited PCa cell proliferation, invasion and androgen-independent proliferation. Moreover, TPM2 overexpression inhibited the growth of subcutaneous xenograft tumors in vivo. Mechanistically, this effect was noted to be dependent on PDZ-binding motif of TPM2. TPM2 competed with YAP1 for binding to PDLIM7 through the PDZ-binding motif. The binding of TPM2 to PDLIM7 subsequently inhibited the nuclear transport function of PDLIM7 for YAP1. YAP1 sequestered in the cytoplasm phosphorylated at S127, resulting in its inactivation or degradation which in turn inhibited the expression of YAP1 downstream target genes.

CONCLUSIONS

This study investigated the role of TPM2, PDLIM7, and YAP1 in PCa progression and castration resistance. TPM2 attenuates progression of PCa by blocking PDLIM7-mediated nuclear translocation of YAP1. Accordingly, targeting the expression or functional modulation of TPM2, PDLIM7, or YAP1 has the potential to be an effective therapeutic approach to reduce PCa proliferation and prevent the progression of castration-resistant prostate cancer (CRPC).

HDAC11 activity contributes to MEK inhibitor escape in uveal melanoma

We previously demonstrated that pan-HDAC inhibitors could limit escape from MEK inhibitor (MEKi) therapy in uveal melanoma (UM) through suppression of AKT and YAP/TAZ signaling. Here, we focused on the role of specific HDACs in therapy adaptation. Class 2 UM displayed higher expression of HDACs 1, 2, and 3 than Class 1, whereas HDACs 6, 8, and 11 were uniformly expressed. Treatment of UM cells with MEKi led to modulation of multiple HDACs, with the strongest increases observed in HDAC11. RNA-seq analysis showed MEKi to decrease the expression of multiple HDAC11 target genes. Silencing of HDAC11 significantly reduced protein deacetylation, enhanced the apoptotic response to MEKi and reduced growth in long-term colony formation assays across multiple UM cell lines. Knockdown of HDAC11 led to decreased expression of TAZ in some UM cell lines, accompanied by decreased YAP/TAZ transcriptional activity and reduced expression of multiple YAP/TAZ target genes. Further studies showed this decrease in TAZ expression to be associated with increased LKB1 activation and modulation of glycolysis. In an in vivo model of uveal melanoma, silencing of HDAC11 limited the escape to MEKi therapy, an effect associated with reduced levels of Ki67 staining and increased cleaved caspase-3. We have demonstrated a novel role for adaptive HDAC11 activity in UM cells, that in some cases modulates YAP/TAZ signaling leading to MEKi escape.

Hippo Signaling in the Ovary: Emerging Roles in Development, Fertility, and Disease

Emerging studies indicate that the Hippo pathway, a highly conserved pathway that regulates organ size control, plays an important role in governing ovarian physiology, fertility, and pathology. Specific to the ovary, the spatiotemporal expression of the major components of the Hippo signaling cascade are observed throughout the reproductive lifespan. Observations from multiple species begin to elucidate the functional diversity and molecular mechanisms of Hippo signaling in the ovary in addition to the identification of interactions with other signaling pathways and responses to various external stimuli. Hippo pathway components play important roles in follicle growth and activation, as well as steroidogenesis, by regulating several key biological processes through mechanisms of cell proliferation, migration, differentiation, and cell fate determination. Given the importance of these processes, dysregulation of the Hippo pathway contributes to loss of follicular homeostasis and reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and ovarian cancers. This review highlights what is currently known about the Hippo pathway core components in ovarian physiology, including ovarian development, follicle development, and oocyte maturation, while identifying areas for future research to better understand Hippo signaling as a multifunctional pathway in reproductive health and biology.

Cardiac fibroblasts and mechanosensation in heart development, health and disease

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.

Mitochondrial Matrix Protease ClpP Agonists Inhibit Cancer Stem Cell Function in Breast Cancer Cells by Disrupting Mitochondrial Homeostasis

Mitochondria are multifaceted organelles which are important for bioenergetics, biosynthesis and signaling in metazoans. Mitochondrial functions are frequently altered in cancer to promote both the energy and the necessary metabolic intermediates for biosynthesis required for tumor growth. Cancer stem cells (CSCs) contribute to chemotherapy resistance, relapse, and metastasis. Recent studies have shown that while non-stem, bulk cancer cells utilize glycolysis, breast CSCs are more dependent on oxidative phosphorylation (OxPhos) and therefore targeting mitochondria may inhibit CSC function. We previously reported that small molecule ONC201, which is an agonist for the mitochondrial caseinolytic protease (ClpP), induces mitochondrial dysfunction in breast cancer cells. In this study, we report that ClpP agonists inhibit breast cancer cell proliferation and CSC function in vitro and in vivo. Mechanistically, we found that OxPhos inhibition downregulates multiple pathways required for CSC function, such as the mevalonate pathway, YAP, Myc, and the HIF pathway. ClpP agonists showed significantly greater inhibitory effect on CSC functions compared with other mitochondria-targeting drugs. Further studies showed that ClpP agonists deplete NAD(P)+ and NAD(P)H, induce redox imbalance, dysregulate one-carbon metabolism and proline biosynthesis. Downregulation of these pathways by ClpP agonists further contribute to the inhibition of CSC function. In conclusion, ClpP agonists inhibit breast CSC functions by disrupting mitochondrial homeostasis in breast cancer cells and inhibiting multiple pathways critical to CSC function.

Significance

ClpP agonists disrupt mitochondrial homeostasis by activating mitochondrial matrix protease ClpP. We report that ClpP agonists inhibit cell growth and cancer stem cell functions in breast cancer models by modulating multiple metabolic pathways essential to cancer stem cell function.

CXCL12/CXCR7/β-arrestin1 biased signal promotes epithelial-to-mesenchymal transition of colorectal cancer by repressing miRNAs through YAP1 nuclear translocation

BACKGROUND

Chemokine CXC motif receptor 7 (CXCR7) is an atypical G protein-coupled receptor (GPCR) that signals in a biased fashion. CXCL12/CXCR7 biased signal has been reported to play crucial roles in multiple stages of colorectal cancer (CRC). However, the mechanism of CXCL12/CXCR7 biased signal in promoting CRC progression and metastasis remains obscure.

RESULTS

We demonstrate that CXCR7 activation promotes EMT and upregulates the expression of Vimentin and doublecortin-like kinase 1 (DCLK1) in CRC cells with concurrent repression of miR-124-3p and miR-188-5p through YAP1 nuclear translocation. Cell transfection and luciferase assay prove that these miRNAs regulate EMT by targeting Vimentin and DCLK1. More importantly, CXCL12/CXCR7/β-arrestin1-mediated biased signal induces YAP1 nuclear translocation, which functions as a transcriptional repressor by interacting with Yin Yang 1 (YY1) and recruiting YY1 to the promoters of miR-124-3p and miR-188-5p. Pharmacological inhibitor of YAP1 suppresses EMT and tumor metastasis upon CXCR7 activation in vivo in tumor xenografts of nude mice and inflammatory colonic adenocarcinoma models. Clinically, the expression of CXCR7 is positively correlated with nuclear YAP1 levels and EMT markers.

CONCLUSIONS

Our studies reveal a novel mechanism and clinical significance of CXCL12/CXCR7 biased signal in promoting EMT and invasion in CRC progression. These findings highlight the potential of targeting YAP1 nuclear translocation in hampering CXCL12/CXCR7 biased signal-induced metastasis of colorectal cancer.

Reciprocal regulation of actin filaments and cellular metabolism

For cells to adhere, migrate and proliferate, remodeling of the actin cytoskeleton is required. This process consumes a large amount of ATP while having an intimate connection with cellular metabolism. Signaling pathways that regulate energy homeostasis can also affect actin dynamics, whereas a variety of actin binding proteins directly or indirectly interact with the anabolic and catabolic regulators in cells. Here, we discuss the inter-regulation between actin filaments and cellular metabolism, reviewing recent discoveries on key metabolic enzymes that respond to actin remodeling as well as historical findings on metabolic stress-induced cytoskeletal reorganization. We also address emerging techniques that would benefit the study of cytoskeletal dynamics and cellular metabolism in high spatial-temporal resolution.

Therapeutic Effect of Melatonin in Premature Ovarian Insufficiency: Hippo Pathway Is Involved

Objective

Premature ovarian insufficiency (POI) is a female reproductive disorder of unknown etiology with no definite pathogenesis. Melatonin (MT) is an endogenous hormone synthesized mainly by pineal cells and has strong endogenous effects in regulating ovarian function. To systematically explore the pharmacological mechanism of MT on POI therapy, a literature review approach was conducted at the signaling pathways level.

Methods

Relevant literatures were searched and downloaded from databases, including PubMed and China National Knowledge Infrastructure, using the keywords “premature ovarian insufficiency,” “Hippo signaling pathways,” and “melatonin.” The search criteria were from 2010 to 2022. Text mining was also performed.

Results

MT is involved in the regulation of Hippo signaling pathway in a variety of modes and has been correlated with ovarian function.

Conclusions

The purpose of this review is to summarize the research progress of Hippo signaling pathways and significance of MT in POI, the potential crosstalk between MT and Hippo signaling pathways, and the prospective therapy.

Clinical potential of the Hippo-YAP pathway in bladder cancer

Bladder cancer (BC) is one of the world’s most frequent cancers. Surgery coupled with adjuvant platinum-based chemotherapy is the current standard of therapy for BC. However, a high proportion of patients progressed to chemotherapy-resistant or even neoplasm recurrence. Hence, identifying novel treatment targets is critical for clinical treatment. Current studies indicated that the Hippo-YAP pathway plays a crucial in regulating the survival of cancer stem cells (CSCs), which is related to the progression and reoccurrence of a variety of cancers. In this review, we summarize the evidence that Hippo-YAP mediates the occurrence, progression and chemotherapy resistance in BC, as well as the role of the Hippo-YAP pathway in regulating bladder cancer stem-like cells (BCSCs). Finally, the clinical potential of Hippo-YAP in the treatment of BC was prospected.

Gankyrin modulated non-small cell lung cancer progression via glycolysis metabolism in a YAP1-dependent manner

Non-small cell lung cancer (NSCLC) is highly malignant and heterogeneous form of lung cancer and involves various oncogene alterations. Glycolysis, an important step in tumor metabolism, is closely related to cancer progression. In this study, we investigated the biological function and mechanism of action of Gankyrin in glycolysis and its association with NSCLC. Analyzed of data from The Cancer Genome Atlas as well as NSCLC specimens and adjacent tissues demonstrated that Gankyrin expression was upregulated in NSCLC tissues compared to adjacent normal tissues. Gankyrin was found to significantly aggravate cancer-related phenotypes, including cell viability, migration, invasion, and epithelial mesenchymal transition (EMT), whereas Gankyrin silencing alleviated the malignant phenotype of NSCLC cells. Our results reveal that Gankyrin exerted its function by regulating YAP1 expression and increasing its nuclear translocation. Importantly, YAP1 actuates glycolysis, which involves glucose uptake, lactic acid production, and ATP generation and thus might contribute to the tumorigenic effect of Gankyrin. Furthermore, the Gankyrin-accelerated glycolysis in NSCLC cells was reversed by YAP1 deficiency. Gankyrin knockdown reduced A549 cell tumorigenesis and EMT and decreased YAP1 expression in a subcutaneous xenograft nude mouse model. In conclusion, both Gankyrin and YAP1 play important roles in tumor metabolism, and Gankyrin-targeted inhibition may be a potential anti-cancer therapeutic strategy for NSCLC.

Physical Exercise and Tumor Energy Metabolism

Evidence supports the antitumoral effects of physical activity, either in experimental animal models or humans. However, the biological mechanisms by which physical exercise modulates tumoral development are still unclear. An important feature of the tumor cells is the altered energy metabolism, often associated with definitions of tumor aggressiveness. Nevertheless, exercise can cause global metabolic changes in the body, as well as modulate tumor metabolism. Here we specifically discuss the metabolic changes found in tumors and how exercise can contribute to anti-tumoral effects by modulating the mitochondrial function, and tricarboxylic acid cycle-related metabolites of cancer cells. The effect of physical exercise on tumor metabolism is a new possibility for comprehension of cancer biology and developing therapies focused on tumor energy metabolism.

Insights Into the Properties, Biological Functions, and Regulation of USP21

Deubiquitylating enzymes (DUBs) antagonize ubiquitination by removing ubiquitin from their substrates. The role of DUBs in controlling various physiological and pathological processes has been extensively studied, and some members of DUBs have been identified as potential therapeutic targets in diseases ranging from tumors to neurodegeneration. Ubiquitin-specific protease 21 (USP21) is a member of the ubiquitin-specific protease family, the largest subfamily of DUBs. Although USP21 was discovered late and early research progress was slow, numerous studies in the last decade have gradually revealed the importance of USP21 in a wide variety of biological processes. In particular, the pro-carcinogenic effect of USP21 has been well elucidated in the last 2 years. In the present review, we provide a comprehensive overview of the current knowledge on USP21, including its properties, biological functions, pathophysiological roles, and cellular regulation. Limited pharmacological interventions for USP21 have also been introduced, highlighting the importance of developing novel and specific inhibitors targeting USP21.

YAP and TAZ: Monocorial and bicorial transcriptional co-activators in human cancers

The transcriptional regulators YAP and TAZ are involved in numerous physiological processes including organ development, growth, immunity and tissue regeneration. YAP and TAZ dysregulation also contribute to tumorigenesis, thereby making them attractive cancer therapeutic targets. Arbitrarily, YAP and TAZ are often considered as a single protein, and are referred to as YAP/TAZ in most studies. However, increasing experimental evidences documented that YAP and TAZ perform both overlapping and distinct functions in several physiological and pathological processes. In addition to regulating distinct processes, YAP and TAZ are also regulated by distinct upstream cues. The aim of the review is to describe the distinct roles of YAP and TAZ focusing particularly on cancer. Therapeutic strategies targeting either YAP and TAZ proteins or only one of them should be carefully evaluated. Selective targeting of YAP or TAZ may in fact impair different pathways and determine diverse clinical outputs.

Unraveling the Biology of Epithelioid Hemangioendothelioma, a TAZ-CAMTA1 Fusion Driven Sarcoma

Simple Summary

Epithelioid hemangioendothelioma (EHE) is a rare vascular cancer that involves a gain-of-function gene fusion involving TAZ, a transcriptional coactivator, and one of two end effectors of the Hippo pathway. Although the activity of TAZ and/or YAP, a paralog of TAZ, is consistently altered in many cancers, genetic alterations involving YAP/TAZ are rare, and the precise mechanisms by which YAP/TAZ are activated are not well understood in most cancers. Because WWTR1(TAZ)–CAMTA1 is the only genetic alteration in approximately half of EHE, EHE is a genetically clean and homogenous system for understanding how the dysregulation of TAZ promotes tumorigenesis. Therefore, by using EHE as a model system, we hope to elucidate the essential biological pathways mediated by TAZ and identify mechanisms to target them. The findings of EHE research can be applied to other cancers that are addicted to high YAP/TAZ activity.

Abstract

The activities of YAP and TAZ, the end effectors of the Hippo pathway, are consistently altered in cancer, and this dysregulation drives aggressive tumor phenotypes. While the actions of these two proteins aid in tumorigenesis in the majority of cancers, the dysregulation of these proteins is rarely sufficient for initial tumor development. Herein, we present a unique TAZ-driven cancer, epithelioid hemangioendothelioma (EHE), which harbors a WWTR1(TAZ)–CAMTA1 gene fusion in at least 90% of cases. Recent investigations have elucidated the mechanisms by which YAP/TAP-fusion oncoproteins function and drive tumorigenesis. This review presents a critical evaluation of this recent work, with a particular focus on how the oncoproteins alter the normal activity of TAZ and YAP, and, concurrently, we generate a framework for how we can target the gene fusions in patients. Since EHE represents a paradigm of YAP/TAZ dysregulation in cancer, targeted therapies for EHE may also be effective against other YAP/TAZ-dependent cancers.

Self-Sustained Regulation or Self-Perpetuating Dysregulation: ROS-dependent HIF-YAP-Notch Signaling as a Double-Edged Sword on Stem Cell Physiology and Tumorigenesis

Organ development, homeostasis, and repair often rely on bidirectional, self-organized cell-niche interactions, through which cells select cell fate, such as stem cell self-renewal and differentiation. The niche contains multiplexed chemical and mechanical factors. How cells interpret niche structural information such as the 3D topology of organs and integrate with multiplexed mechano-chemical signals is an open and active research field. Among all the niche factors, reactive oxygen species (ROS) have recently gained growing interest. Once considered harmful, ROS are now recognized as an important niche factor in the regulation of tissue mechanics and topology through, for example, the HIF-YAP-Notch signaling pathways. These pathways are not only involved in the regulation of stem cell physiology but also associated with inflammation, neurological disorder, aging, tumorigenesis, and the regulation of the immune checkpoint molecule PD-L1. Positive feedback circuits have been identified in the interplay of ROS and HIF-YAP-Notch signaling, leading to the possibility that under aberrant conditions, self-organized, ROS-dependent physiological regulations can be switched to self-perpetuating dysregulation, making ROS a double-edged sword at the interface of stem cell physiology and tumorigenesis. In this review, we discuss the recent findings on how ROS and tissue mechanics affect YAP-HIF-Notch-PD-L1 signaling, hoping that the knowledge can be used to design strategies for stem cell-based and ROS-targeting therapy and tissue engineering.

Functions of Yes-association protein (YAP) in cancer progression and anticancer therapy resistance

The Hippo pathway, a highly conserved kinase cascade, regulates cell proliferation, apoptosis, organ size, and tissue homeostasis. Dysregulation of this pathway reportedly plays an important role in the progression of various human cancers. Yes-association protein (YAP), the Hippo pathway’s core effector, is considered a marker for cancer therapy and patient prognosis. In addition, studies have indicated that YAP is involved in promoting anticancer drug resistance. This review summarizes current knowledge on YAP’s role in cancer progression, anticancer drug resistance, and advances in the development of YAP-targeting drugs. A thorough understanding of the complex interactions among molecular, cellular, and environmental factors concerning YAP function in cancer progression may provide new insight into the underlying mechanism of anticancer drug resistance. It might lead to improved prognosis through novel combined therapies.

YAP regulates an SGK1/mTORC1/SREBP-dependent lipogenic program to support proliferation and tissue growth

The coordinated regulation of growth control and metabolic pathways is required to meet the energetic and biosynthetic demands associated with proliferation. Emerging evidence suggests that the Hippo pathway effector Yes-associated protein 1 (YAP) reprograms cellular metabolism to meet the anabolic demands of growth, although the mechanisms involved are poorly understood. Here, we demonstrate that YAP co-opts the sterol regulatory element-binding protein (SREBP)-dependent lipogenic program to facilitate proliferation and tissue growth. Mechanistically, YAP stimulates de novo lipogenesis via mechanistic target of rapamcyin (mTOR) complex 1 (mTORC1) signaling and subsequent activation of SREBP. Importantly, YAP-dependent regulation of serum- and glucocorticoid-regulated kinase 1 (SGK1) is required to activate mTORC1/SREBP and stimulate de novo lipogenesis. We also find that the SREBP target genes fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD) are conditionally required to support YAP-dependent proliferation and tissue growth. These studies reveal that de novo lipogenesis is a metabolic vulnerability that can be targeted to disrupt YAP-dependent proliferation and tissue growth.

Potential Role of Exercise in Regulating YAP and TAZ During Cardiomyocytes Aging

Adaptation of cardiac muscle to regular exercise results in morphological and structural changes known as physiological cardiac hypertrophy, to which the Hippo signaling pathway might have contributed. Two major terminal effectors in the Hippo signaling pathway are Yes-associated protein (YAP) and its homolog transcriptional coactivator with PDZ-binding motif (TAZ). The latest studies have reported the role of YAP and TAZ in different life stages, such as in fetal, neonatal, and adult hearts. Their regulation might involve several mechanisms and effectors. One of the possible coregulators is exercise. Exercise plays a role in cardiomyocyte hypertrophic changes during different stages of life, including in aged hearts. YAP/TAZ signaling pathway has a role in physiological cardiac hypertrophy induced by exercise and is associated with cardiac remodelling. Thus, it can be believed that exercise has roles in activating the signaling pathway of YAP and TAZ in aged cardiomyocytes. However, the studies regarding the roles of YAP and TAZ during cardiomyocyte aging are limited. The primary purpose of this review is to explore the response of cardiovascular aging to exercise via signaling pathway of YAP and TAZ.

The YAP/TAZ Signaling Pathway in the Tumor Microenvironment and Carcinogenesis: Current Knowledge and Therapeutic Promises

The yes-associated protein (YAP) and the transcriptional coactivator with PDZ-binding motif (TAZ) are transcriptional coactivators, members of the Hippo signaling pathway, which play a critical role in cell growth regulation, embryonic development, regeneration, proliferation, and cancer origin and progression. The mechanism involves the nuclear binding of the un-phosphorylated YAP/TAZ complex to release the transcriptional enhanced associate domain (TEAD) from its repressors. The active ternary complex is responsible for the aforementioned biological effects. Overexpression of YAP/TAZ has been reported in cancer stem cells and tumor resistance. The resistance involves chemotherapy, targeted therapy, and immunotherapy. This review provides an overview of YAP/TAZ pathways’ role in carcinogenesis and tumor microenvironment. Potential therapeutic alternatives are also discussed.

Hippo Pathway in Regulating Drug Resistance of Glioblastoma

Glioblastoma (GBM) represents the most common and malignant tumor of the Central Nervous System (CNS), affecting both children and adults. GBM is one of the deadliest tumor types and it shows a strong multidrug resistance (MDR) and an immunosuppressive microenvironment which remain a great challenge to therapy. Due to the high recurrence of GBM after treatment, the understanding of the chemoresistance phenomenon and how to stimulate the antitumor immune response in this pathology is crucial. The deregulation of the Hippo pathway is involved in tumor genesis, chemoresistance and immunosuppressive nature of GBM. This pathway is an evolutionarily conserved signaling pathway with a kinase cascade core, which controls the translocation of YAP (Yes-Associated Protein)/TAZ (Transcriptional Co-activator with PDZ-binding Motif) into the nucleus, leading to regulation of organ size and growth. With this review, we want to highlight how chemoresistance and tumor immunosuppression work in GBM and how the Hippo pathway has a key role in them. We linger on the role of the Hippo pathway evaluating the effect of its de-regulation among different human cancers. Moreover, we consider how different pathways are cross-linked with the Hippo signaling in GBM genesis and the hypothetical mechanisms responsible for the Hippo pathway activation in GBM. Furthermore, we describe various drugs targeting the Hippo pathway. In conclusion, all the evidence described largely support a strong involvement of the Hippo pathway in gliomas progression, in the activation of chemoresistance mechanisms and in the development of an immunosuppressive microenvironment. Therefore, this pathway is a promising target for the treatment of high grade gliomas and in particular of GBM.

Crosstalk between KRAS, SRC and YAP Signaling in Pancreatic Cancer: Interactions Leading to Aggressive Disease and Drug Resistance

Pancreatic ductal adenocarcinoma (PDAC), the predominant form of pancreatic cancer, remains a devastating disease. The purpose of this review is to highlight recent literature on mechanistic and translational developments that advance our understanding of a complex crosstalk between KRAS, YAP and Src tyrosine kinase family (SFK) in PDAC development and maintenance. We discuss recent studies indicating the importance of RAS dimerization in signal transduction and new findings showing that the potent pro-oncogenic members of the SFK phosphorylate and inhibit RAS function. These surprising findings imply that RAS may not play a crucial role in maintaining certain subtypes of PDAC. In support of this interpretation, current evidence indicates that the survival of the basal-like subtype of PDAC is less dependent on RAS but relies, at least in part, on the activity of YAP/TAZ. Based on current evidence, we propose that SFK propels PDAC cells to a state of high metastasis, epithelial-mesenchymal transition (EMT) and reduced dependence on KRAS signaling, salient features of the aggressive basal-like/squamous subtype of PDAC. Strategies for PDAC treatment should consider the opposite effects of tyrosine phosphorylation on KRAS and SFK/YAP in the design of drug combinations that target these novel crosstalk mechanisms and overcome drug resistance.

LncRNA coordinates Hippo and mTORC1 pathway activation in cancer

The Hippo and mammalian target of rapamycin complex 1 (mTORC1) pathways are the two predominant pathways that regulate tumour growth and metastasis. Therefore, we explored the potential crosstalk between these two functionally relevant pathways to coordinate their tumour growth-control functions. We found that a Hippo pathway-related long noncoding RNA, HPR, directly interacts with Raptor, an essential component of mTORC1, to upregulate mTORC1 activation by impairing the phosphorylation of Raptor by AMPK. Knockdown or knockout of HPR in breast cancer and cholangiocarcinoma cells led to a reduction in tumour growth. Compared with HPR WT cells, HPR-overexpressing cells exhibited nuclear accumulation of YAP1, and significantly blocked the downregulation of mTORC1 signalling induced by energy stress. Thus, our study reveals a direct link between the Hippo and mTORC1 pathways in the control of tumour growth.

The hippo pathway: A master regulator of liver metabolism, regeneration, and disease

The liver is the only visceral organ in the body with a tremendous capacity to regenerate in response to insults that induce inflammation, cell death, and injury. Liver regeneration is a complicated process involving a well-orchestrated activation of non-parenchymal cells in the injured area and proliferation of undamaged hepatocytes. Furthermore, the liver has a Hepatostat, defined as adjustment of its volume to that required for homeostasis. Understanding the mechanisms that control different steps of liver regeneration is critical to informing therapies for liver repair, to help patients with liver disease. The Hippo signaling pathway is well known for playing an essential role in the control and regulation of liver size, regeneration, stem cell self-renewal, and liver cancer. Thus, the Hippo pathway regulates dynamic cell fates in liver, and in absence of its downstream effectors YAP and TAZ, liver regeneration is severely impaired, and the proliferative expansion of liver cells blocked. We will mainly review upstream mechanisms activating the Hippo signaling pathway following partial hepatectomy in mouse model and patients, its roles during different steps of liver regeneration, metabolism, and cancer. We will also discuss how targeting the Hippo signaling cascade might improve liver regeneration and suppress liver tumorigenesis.

YAP1 nuclear efflux and transcriptional reprograming follow membrane diminution upon VSV-G-induced cell fusion

Cells in many tissues, such as bone, muscle, and placenta, fuse into syncytia to acquire new functions and transcriptional programs. While it is known that fused cells are specialized, it is unclear whether cell-fusion itself contributes to programmatic-changes that generate the new cellular state. Here, we address this by employing a fusogen-mediated, cell-fusion system to create syncytia from undifferentiated cells. RNA-Seq analysis reveals VSV-G-induced cell fusion precedes transcriptional changes. To gain mechanistic insights, we measure the plasma membrane surface area after cell-fusion and observe it diminishes through increases in endocytosis. Consequently, glucose transporters internalize, and cytoplasmic glucose and ATP transiently decrease. This reduced energetic state activates AMPK, which inhibits YAP1, causing transcriptional-reprogramming and cell-cycle arrest. Impairing either endocytosis or AMPK activity prevents YAP1 inhibition and cell-cycle arrest after fusion. Together, these data demonstrate plasma membrane diminishment upon cell-fusion causes transient nutrient stress that may promote transcriptional-reprogramming independent from extrinsic cues.

Metabolic landscapes in sarcomas

Metabolic rewiring offers novel therapeutic opportunities in cancer. Until recently, there was scant information regarding soft tissue sarcomas, due to their heterogeneous tissue origin, histological definition and underlying genetic history. Novel large-scale genomic and metabolomics approaches are now helping stratify their physiopathology. In this review, we show how various genetic alterations skew activation pathways and orient metabolic rewiring in sarcomas. We provide an update on the contribution of newly described mechanisms of metabolic regulation. We underscore mechanisms that are relevant to sarcomagenesis or shared with other cancers. We then discuss how diverse metabolic landscapes condition the tumor microenvironment, anti-sarcoma immune responses and prognosis. Finally, we review current attempts to control sarcoma growth using metabolite-targeting drugs.

Metformin: review of epidemiology and mechanisms of action in pancreatic cancer

Pancreatic ductal adenocarcinoma continues to be a lethal disease, for which efficient treatment options are very limited. Increasing efforts have been taken to understand how to prevent or intercept this disease at an early stage. There is convincing evidence from epidemiologic and preclinical studies that the antidiabetic drug metformin possesses beneficial effects in pancreatic cancer, including reducing the risk of developing the disease and improving survival in patients with early-stage disease. This review will summarize the current literature about the epidemiological data on metformin and pancreatic cancer as well as describe the preclinical evidence illustrating the anticancer effects of metformin in pancreatic cancer. Underlying mechanisms and targets of metformin will also be discussed. These include direct effects on transformed pancreatic epithelial cells and indirect, systemic effects on extra-pancreatic tissues.

The Hippo Pathway: A Master Regulatory Network Important in Cancer

The Hippo pathway is pervasively activated and has been well recognized to play critical roles in human cancer. The deregulation of Hippo signaling involved in cancer development, progression, and resistance to cancer treatment have been confirmed in several human cancers. Its biological significance and deregulation in cancer have drawn increasing interest in the past few years. A fundamental understanding of the complexity of the Hippo pathway in cancer is crucial for improving future clinical interventions and therapy for cancers. In this review, we try to clarify the complex regulation and function of the Hippo signaling network in cancer development, including its role in signal transduction, metabolic regulation, and tumor development, as well as tumor therapies targeting the Hippo pathway.

Vascular Metabolism as Driver of Atherosclerosis: Linking Endothelial Metabolism to Inflammation

The endothelium is a crucial regulator of vascular homeostasis by controlling barrier integrity as well acting as an important signal transducer, thereby illustrating that endothelial cells are not inert cells. In the context of atherosclerosis, this barrier function is impaired and endothelial cells become activated, resulting in the upregulation of adhesion molecules, secretion of cytokines and chemokines and internalization of integrins. Finally, this leads to increased vessel permeability, thereby facilitating leukocyte extravasation as well as fostering a pro-inflammatory environment. Additionally, activated endothelial cells can form migrating tip cells and proliferative stalk cells, resulting in the formation of new blood vessels. Emerging evidence has accumulated indicating that cellular metabolism is crucial in fueling these pro-atherosclerotic processes, including neovascularization and inflammation, thereby contributing to plaque progression and altering plaque stability. Therefore, further research is necessary to unravel the complex mechanisms underlying endothelial cell metabolic changes, and exploit this knowledge for finding and developing potential future therapeutic strategies. In this review we discuss the metabolic alterations endothelial cells undergo in the context of inflammation and atherosclerosis and how this relates to changes in endothelial functioning. Finally, we will describe several metabolic targets that are currently being used for therapeutic interventions.

Progress in the mechanical modulation of cell functions in tissue engineering

In mammals, mechanics at multiple stages-nucleus to cell to ECM-underlie multiple physiological and pathological functions from its development to reproduction to death. Under this inspiration, substantial research has established the role of multiple aspects of mechanics in regulating fundamental cellular processes, including spreading, migration, growth, proliferation, and differentiation. However, our understanding of how these mechanical mechanisms are orchestrated or tuned at different stages to maintain or restore the healthy environment at the tissue or organ level remains largely a mystery. Over the past few decades, research in the mechanical manipulation of the surrounding environment-known as substrate or matrix or scaffold on which, or within which, cells are seeded-has been exceptionally enriched in the field of tissue engineering and regenerative medicine. To do so, traditional tissue engineering aims at recapitulating key mechanical milestones of native ECM into a substrate for guiding the cell fate and functions towards specific tissue regeneration. Despite tremendous progress, a big puzzle that remains is how the cells compute a host of mechanical cues, such as stiffness (elasticity), viscoelasticity, plasticity, non-linear elasticity, anisotropy, mechanical forces, and mechanical memory, into many biological functions in a cooperative, controlled, and safe manner. High throughput understanding of key cellular decisions as well as associated mechanosensitive downstream signaling pathway(s) for executing these decisions in response to mechanical cues, solo or combined, is essential to address this issue. While many reports have been made towards the progress and understanding of mechanical cues-particularly, substrate bulk stiffness and viscoelasticity-in regulating the cellular responses, a complete picture of mechanical cues is lacking. This review highlights a comprehensive view on the mechanical cues that are linked to modulate many cellular functions and consequent tissue functionality. For a very basic understanding, a brief discussion of the key mechanical players of ECM and the principle of mechanotransduction process is outlined. In addition, this review gathers together the most important data on the stiffness of various cells and ECM components as well as various tissues/organs and proposes an associated link from the mechanical perspective that is not yet reported. Finally, beyond addressing the challenges involved in tuning the interplaying mechanical cues in an independent manner, emerging advances in designing biomaterials for tissue engineering are also explored.

Moonlighting Metabolic Enzymes in Cancer: New Perspectives on the Redox Code

Significance: Metabolic reprogramming is considered to be a critical adaptive biological event that fulfills the energy and biomass demands for cancer cells. One hallmark of metabolic reprogramming is reduced oxidative phosphorylation and enhanced aerobic glycolysis. Such metabolic abnormalities contribute to the accumulation of reactive oxygen species (ROS), the by-products of metabolic pathways. Emerging evidence suggests that ROS can in turn directly or indirectly affect the expression, activity, or subcellular localization of metabolic enzymes, contributing to the moonlighting functions outside of their primary roles. This review summarizes the multifunctions of metabolic enzymes and the involved redox modification patterns, which further reveal the inherent connection between metabolism and cellular redox state. Recent Advances: These noncanonical functions of metabolic enzymes involve the regulation of epigenetic modifications, gene transcription, post-translational modification, cellular antioxidant capacity, and many other fundamental cellular events. The multifunctional properties of metabolic enzymes further expand the metabolic dependencies of cancer cells, and confer cancer cells with a means of adapting to diverse environmental stimuli. Critical Issues: Deciphering the redox-manipulated mechanisms with specific emphasis on the moonlighting function of metabolic enzymes is important for clarifying the pertinence between metabolism and redox processes. Future Directions: Investigation of the redox-regulated moonlighting functions of metabolic enzymes will shed new lights into the mechanism by which metabolic enzymes gain noncanonical functions, and yield new insights into the development of novel therapeutic strategies for cancer treatment by targeting metabolic-redox abnormalities. Antioxid. Redox Signal. 34, 979-1003.

Hepatocyte-specific TAZ deletion downregulates p62/ Sqstm1 expression in nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is characterized by inflammation, hepatocellular injury, and different degrees of fibrosis. Previous studies have indicated that the transcriptional coactivator with PDZ-binding motif TAZ (WWTR1) is correlated with the increased level of liver cholesterol which suppresses TAZ proteasomal degradation and promotes fibrotic NASH by activating soluble adenylyl cyclase -calcium-RhoA pathway. However, the exact mechanism by which TAZ promotes inflammatory and hepatocyte injury has not yet been fully addressed. Reportedly, p62/Sqstm1plays a pivotal role in inflammatory and hepatocyte injury during NASH development. Here, we demonstrated that p62/Sqstm1 was overexpressed in the livers of mouse NASH models in a TAZ-dependent manner. In addition, hepatocyte-specific TAZ deletion reduced p62/Sqstm1 both in vitro and in vivo. Strikingly, luciferase reporter data demonstrated that p62/Sqstm1 is a TAZ/TEAD target gene and can be transcriptionally regulated by TAZ, indicating that hepatocyte-specific TAZ deletion downregulates p62/Sqstm1 expression in NASH.

Crosstalk between mechanotransduction and metabolism

Mechanical forces shape cells and tissues during development and adult homeostasis. In addition, they also signal to cells via mechanotransduction pathways to control cell proliferation, differentiation and death. These processes require metabolism of nutrients for both energy generation and biosynthesis of macromolecules. However, how cellular mechanics and metabolism are connected is still poorly understood. Here, we discuss recent evidence indicating how the mechanical cues exerted by the extracellular matrix (ECM), cell-ECM and cell-cell adhesion complexes influence metabolic pathways. Moreover, we explore the energy and metabolic requirements associated with cell mechanics and ECM remodelling, implicating a reciprocal crosstalk between cell mechanics and metabolism.

Heart failure impairs the mechanotransduction properties of human cardiac pericytes

The prominent impact that coronary microcirculation disease (CMD) exerts on heart failure symptoms and prognosis, even in the presence of macrovascular atherosclerosis, has been recently acknowledged. Experimental delivery of pericytes in non-revascularized myocardial infarction improves cardiac function by stimulating angiogenesis and myocardial perfusion. Aim of this work is to verify if pericytes (Pc) residing in ischemic failing human hearts display altered mechano-transduction properties and to assess which alterations of the mechano-sensing machinery are associated with the observed impaired response to mechanical cues. RESULTS: Microvascular rarefaction and defects of YAP/TAZ activation characterize failing human hearts. Although both donor (D-) and explanted (E-) heart derived cardiac Pc support angiogenesis, D-Pc exert this effect significantly better than E-Pc. The latter are characterized by reduced focal adhesion density, decreased activation of the focal adhesion kinase (FAK)/ Crk-associated substrate (CAS) pathway, low expression of caveolin-1, and defective transduction of extracellular stiffness into cytoskeletal stiffening, together with an impaired response to both fibronectin and lysophosphatidic acid. Importantly, Mitogen-activated protein kinase kinase inhibition restores YAP/TAZ nuclear translocation. CONCLUSION: Heart failure impairs Pc mechano-transduction properties, but this defect could be reversed pharmacologically.

The mevalonate pathway promotes the metastasis of osteosarcoma by regulating YAP1 activity via RhoA

Osteosarcoma is the most common malignant bone tumour, and the metastasis of osteosarcoma is an important cause of death. Evidence has shown that the mevalonate pathway is highly activated and is expected to be a new target for tumour therapy. In this study, we investigated the effect of mevalonate signalling on osteosarcoma metastasis and its molecular mechanism. First, we found that the key rate-limiting enzyme of mevalonate signalling, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), was highly expressed in osteosarcoma cells, and inhibition of HMGCR with simvastatin significantly inhibited the motility of 143B cells. Next, we found that YAP1 activity was significantly upregulated in osteosarcoma cells and that YAP1 knockdown inhibited the motility of 143B cells. We also found that the mevalonate pathway regulated the motility of 143B cells by modulating YAP1 phosphorylation and cellular localization. Moreover, we found that the activity of YAP1 was regulated by the mevalonate pathway by modulating the cell membrane localization of RhoA. Finally, we demonstrated that inhibition of the mevalonate pathway notably reduced the lung metastasis of 143B cells, as reflected by the decreased incidence and number of metastatic nodules and the increased survival time of the nude mice. Taken together, our findings suggest that the mevalonate pathway can promote the metastasis of osteosarcoma by activating YAP1 via RhoA. Inhibition of the mevalonate pathway may be a promising therapeutic strategy for osteosarcoma metastasis.

Synergistic antitumor interaction of valproic acid and simvastatin sensitizes prostate cancer to docetaxel by targeting CSCs compartment via YAP inhibition

BACKGROUND

Despite the introduction of several novel therapeutic approaches that improved survival, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease. Herein we report the synergistic antitumor interaction between two well-known drugs used for years in clinical practice, the antiepileptic agent with histone deacetylase inhibitory activity valproic acid and the cholesterol lowering agent simvastatin, in mCRPC models.

METHODS

Synergistic anti-tumor effect was assessed on PC3, 22Rv1, DU145, DU145R80, LNCaP prostate cancer cell lines and EPN normal prostate epithelial cells, by calculating combination index (CI), caspase 3/7 activation and colony formation assays as well as on tumor spheroids and microtissues scored with luminescence 3D-cell viability assay. Cancer stem cells (CSC) compartment was studied evaluating specific markers by RT-PCR, western blotting and flow cytometry as well as by limiting dilution assay. Cholesterol content was evaluated by ¹H-NMR. Overexpression of wild-type YAP and constitutively active YAP5SA were obtained by lipofectamine-based transfection and evaluated by immunofluorescence, western blotting and RT-PCR. 22Rv1 R_39 docetaxel resistant cells were selected by stepwise exposure to increasing drug concentrations. In vivo experiments were performed on xenograft models of DU145R80, 22Rv1 parental and docetaxel resistant cells, in athymic mice.

RESULTS

We demonstrated the capacity of the combined approach to target CSC compartment by a novel molecular mechanism based on the inhibition of YAP oncogene via concurrent modulation of mevalonate pathway and AMPK. Because both CSCs and YAP activation have been associated with chemo-resistance, we tested if the combined approach can potentiate docetaxel, a standard of care in mCRCP treatment. Indeed, we demonstrated, both in vitro and in vivo models, the ability of valproic acid/simvastatin combination to sensitize mCRPC cells to docetaxel and to revert docetaxel-resistance, by mevalonate pathway/YAP axis modulation.

CONCLUSION

Overall, mCRPC progression and therapeutic resistance driven by CSCs via YAP, can be tackled by the combined repurposing of two generic and safe drugs, an approach that warrants further clinical development in this disease.

Arginine infusion rescues ovarian follicular development in feed-restricted Hu sheep during the luteal phase

The aim of this study was to investigate the molecular mechanisms of arginine (Arg) on follicular development of acute feed-restricted ewes during the luteal phase. From day 6 of the estrous cycle, 24 multiparous Hu sheep were randomly assigned into three groups: control group (a maintenance diet; n = 6), feed restriction group (0.5 maintenance diet, saline infusion; n = 9) and Arg treatment group (0.5 maintenance diet, infusion with 155 μmol of Arg-HCl/kg body weight; n = 9). The intravenous administrations were performed three times per day from day 6 to day 15 of the estrous cycle. At the end of treatment, the hypothalamus and pituitary were collected, as well as the follicular fluid (FF) and granulose cells (GCs) in the ≥2.5 mm follicles. The transcription level of NPVF was significantly increased, and the expression level of GNRH was significantly decreased in the hypothalamus with feed restriction. In addition, feed restriction significantly decreased the number of ≥2.5 mm follicles in the ovaries. In the ≥2.5 mm follicles, feed restriction significantly increased estradiol (E₂) level in FF and the expression levels of steroidogenesis related genes (STAR, 3BHSD and CYP19A1) in GCs, while significantly decreased the expressions of FSHR and cell proliferation related genes (YAP1, CCND1 and PCNA) in GCs. Moreover, the activities of glucose metabolism enzymes (PFKP and G6PDH) were significantly decreased in GCs of the ≥2.5 mm follicles with feed restriction. Interestingly, as a precursor of nitric oxide, Arg supplementation can rescue the effects of feed restriction on follicular development by enhancing glucose metabolism and cell proliferation of GCs, and alleviating the abnormal E₂ secretion in the ≥2.5 mm follicles, accompanied with recovering the expressions of NPVF and GNRH in the hypothalamus. These findings will be helpful for understanding the role of nutrition and Arg in sheep follicular development.

Ligation of HLA Class I Molecules Induces YAP Activation through Src in Human Endothelial Cells

Ab cross-linking of HLA class I (HLA I) molecules on the surface of endothelial cells (EC) triggers proliferative and prosurvival intracellular signaling, which is implicated in the process of chronic allograft rejection, also known as transplant vasculopathy. Despite the importance of Ab-mediated rejection in transplantation, the mechanisms involved remain incompletely understood. In this study, we examined the regulation of yes-associated protein (YAP) localization, phosphorylation, and transcriptional activity in human ECs challenged with Abs that bind HLA I. In unstimulated ECs, YAP localized mainly in the cytoplasm. Stimulation of these cells with Ab W6/32 induced marked translocation of YAP to the nucleus. The nuclear import of YAP was associated with a rapid decrease in YAP phosphorylation at Ser¹²⁷ and Ser³⁹⁷, sites targeted by LATS1/2 and with the expression of YAP-regulated genes, including connective tissue growth factor (CTGF), and cysteine-rich angiogenic inducer 61 (CYR61). Transfection of small interfering RNAs targeting YAP/TAZ blocked the migration of ECs stimulated by ligation of HLA I, indicating that YAP mediates the increase in EC migration induced by HLA I ligation. Treatment of intact ECs with Src family inhibitors induced cytoplasmic localization of YAP in unstimulated ECs and, strikingly, blocked the nuclear import of YAP induced by Ab-induced HLA I activation in these cells and the increase in the expression of the YAP-regulated genes CTGF and CYR61 induced by HLA I stimulation. Our results identify the Src/YAP axis as a key player in promoting the proliferation and migration of ECs that are critical in the pathogenesis of transplant vasculopathy.

Integrins meet complement: The evolutionary tip of an iceberg orchestrating metabolism and immunity

Immunologists have recently realized that there is more to the classic innate immune sensor systems than just mere protection against invading pathogens. It is becoming increasingly clear that such sensors, including the inflammasomes, toll-like receptors, and the complement system, are heavily involved in the regulation of basic cell physiological processes and particularly those of metabolic nature. In fact, their "non-canonical" activities make sense as no system directing immune cell activity can perform such task without the need for energy. Further, many of these ancient immune sensors appeared early and concurrently during evolution, particularly during the developmental leap from the single-cell organisms to multicellularity, and therefore crosstalk heavily with each other. Here, we will review the current knowledge about the emerging cooperation between the major inter-cell communicators, integrins, and the cell-autonomous intracellularly and autocrine-active complement, the complosome, during the regulation of single-cell metabolism. LINKED ARTICLES: This article is part of a themed issue on Canonical and non-canonical functions of the complement system in health and disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.14/issuetoc.