bims-pideca 2019-11-03 papers

bims-pideca

Biomed News

on Class IA PI3K signalling in development and cancer

Issue of 2019‒11‒03
twenty papers selected by
Ralitsa Radostinova Madsen
University College London Cancer Institute

Structural mechanism of a Rag GTPase activation checkpoint by the lysosomal folliculin complex.
CD146 Regulates Growth Factor-Induced mTORC2 Activity Independent of the PI3K and mTORC1 Pathways.
A PDGFRβ-PI3K signaling axis mediates periosteal cell activation during fracture healing.
Tsc1 represses parvalbumin expression and fast-spiking properties in somatostatin lineage cortical interneurons.
Amino Acids License Kinase mTORC1 Activity and Treg Cell Function via Small G Proteins Rag and Rheb.
Revising PTEN in the Era of Immunotherapy: New Perspectives for an Old Story.
Insulin Receptor Trafficking: Consequences for Insulin Sensitivity and Diabetes.
FKBP4 connects mTORC2 and PI3K to activate the PDK1/Akt-dependent cell proliferation signaling in breast cancer.
Folliculin Interacting Protein 1 Maintains Metabolic Homeostasis during B Cell Development by Modulating AMPK, mTORC1, and TFE3.
Controversies around epithelial-mesenchymal plasticity in cancer metastasis.
Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.
The comprehensive role of E-cadherin in maintaining prostatic epithelial integrity during oncogenic transformation and tumor progression.
Akt1 and Akt2 Isoforms Play Distinct Roles in Regulating the Development of Inflammation and Fibrosis Associated with Alcoholic Liver Disease.
Stopping transformed cancer cell growth by rigidity sensing.
Temporal patterns of lipolytic regulators in adipose tissue after acute growth hormone exposure in human subjects: A randomized controlled crossover trial.
In vitro culture of cynomolgus monkey embryos beyond early gastrulation.
Microenvironmental IL1β promotes breast cancer metastatic colonisation in the bone via activation of Wnt signalling.
Tackling MARCKS-PIP3 circuit attenuates fibroblast activation and fibrosis progression.
Essentiality of fatty acid synthase in the 2D to anchorage-independent growth transition in transforming cells.
Pathological features of vessel co-option versus sprouting angiogenesis.

Science. 2019 Oct 31. pii: eaax0364. [Epub ahead of print]

Structural mechanism of a Rag GTPase activation checkpoint by the lysosomal folliculin complex.

Rosalie E Lawrence, Simon A Fromm, Yangxue Fu, Adam L Yokom, Do Jin Kim, Ashley M Thelen, Lindsey N Young, Chun-Yan Lim, Avi J Samelson, James H Hurley, Roberto Zoncu.

The tumor suppressor folliculin (FLCN) enables nutrient-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) protein kinase via its guanosine triphosphatase (GTPase) Activating Protein (GAP) activity toward the GTPase RagC. Concomitant with mTORC1 inactivation by starvation, FLCN relocalizes from the cytosol to lysosomes. To determine the lysosomal function of FLCN, we reconstituted the lysosomal FLCN complex (LFC) containing FLCN, its partner FLCN-interacting protein 2 (FNIP2), the RagAGDP:RagCGTP GTPases as they exist in the starved state with their lysosomal anchor Ragulator complex, and determined its cryo-EM structure to 3.6 Å. The RagC-GAP activity of FLCN was inhibited within LFC, due to displacement of a catalytically required Arginine in FLCN from the RagC nucleotide. Disassembly of the LFC and release of the RagC-GAP activity of FLCN enabled mTORC1-dependent regulation of the master regulator of lysosomal biogenesis, transcription factor E3, implicating the LFC as a checkpoint in mTORC1 signaling.

DOI: https://doi.org/10.1126/science.aax0364
Cell Rep. 2019 Oct 29. pii: S2211-1247(19)31235-5. [Epub ahead of print]29(5): 1311-1322.e5

CD146 Regulates Growth Factor-Induced mTORC2 Activity Independent of the PI3K and mTORC1 Pathways.

Wenyi Xu, Huijuan Hua, Yueh-Ho Chiu, Guannan Li, Huihan Zhi, Zhengquan Yu, Fazheng Ren, Yongting Luo, Wei Cui.

  The mechanistic target of rapamycin complex 2 (mTORC2) coordinates cell proliferation, survival, and metabolism with environmental inputs, yet how extracellular stimuli such as growth factors (GFs) activate mTORC2 remains enigmatic. Here we demonstrate that in human endothelial cells, activation of mTORC2 signaling by GFs is mediated by transmembrane cell adhesion protein CD146. Upon GF stimulation, the cytoplasmic tail of CD146 is phosphorylated, which permits its positively charged, juxtamembrane KKGK motif to interact with Rictor, the defining subunit of mTORC2. The formation of the CD146-Rictor/mTORC2 complex protects Rictor from ubiquitin-proteasome-mediated degradation, thereby specifically upregulating mTORC2 activity with no intervention of the PI3K and mTORC1 pathways. This CD146-mediated mTORC2 activation in response to GF stimulation promotes cell proliferation and survival. Therefore, our findings identify a molecular mechanism by which extracellular stimuli regulate mTORC2 activity, linking environmental cues with mTORC2 regulation.

Keywords:  CD146; PI3K; Rictor; cell proliferation; mTORC1; mTORC2; signal transduction

DOI:  https://doi.org/10.1016/j.celrep.2019.09.047
PLoS One. 2019 ;14(10): e0223846

A PDGFRβ-PI3K signaling axis mediates periosteal cell activation during fracture healing.

Laura Doherty, Jungeun Yu, Xi Wang, Kurt D Hankenson, Ivo Kalajzic, Archana Sanjay.

Insufficient and delayed fracture healing remain significant public health problems with limited therapeutic options. Phosphoinositide 3-kinase (PI3K) signaling, a major pathway involved in regulation of fracture healing, promotes proliferation, migration, and differentiation of osteoprogenitors. We have recently reported that knock-in mice with a global increase in PI3K signaling (gCblYF) show enhanced femoral fracture healing characterized by an extraordinary periosteal response to injury. Interestingly, of all growth factor receptors involved in fracture healing, PI3K directly binds only to PDGFR. Given these findings, we hypothesized a PDGFR-PI3K interaction is necessary for mediating robust periosteal cell activation following fracture. In this study, we isolated primary periosteal cells from gCblYF mice to analyze cross-talk between the PDGFRβ and PI3K signaling pathways. We found PDGFRβ signaling contributes to robust Akt phosphorylation in periosteal cells in comparison with other growth factor signaling pathways. Additionally, we performed femoral fractures on gCblYF mice with a conditional removal of PDGFRβ in mesenchymal progenitors using inducible alpha smooth muscle actin (αSMA) CreERT2 mice. Our studies showed that depletion of PDGFRβ signaling within these progenitors in the early phase of fracture healing significantly abrogates PI3K-mediated periosteal activation and proliferation three days after fracture. Combined, these results suggest that PDGFRβ signaling through PI3K is necessary for robust periosteal activation in the earliest phases of fracture healing.

DOI: https://doi.org/10.1371/journal.pone.0223846
Nat Commun. 2019 Nov 01. 10(1): 4994

Tsc1 represses parvalbumin expression and fast-spiking properties in somatostatin lineage cortical interneurons.

Ruchi Malik, Emily Ling-Lin Pai, Anna N Rubin, April M Stafford, Kartik Angara, Petros Minasi, John L Rubenstein, Vikaas S Sohal, Daniel Vogt.

Medial ganglionic eminence (MGE)-derived somatostatin (SST)+ and parvalbumin (PV)+ cortical interneurons (CINs), have characteristic molecular, anatomical and physiological properties. However, mechanisms regulating their diversity remain poorly understood. Here, we show that conditional loss of the Tuberous Sclerosis Complex (TSC) gene, Tsc1, which inhibits the mammalian target of rapamycin (MTOR), causes a subset of SST+ CINs, to express PV and adopt fast-spiking (FS) properties, characteristic of PV+ CINs. Milder intermediate phenotypes also occur when only one allele of Tsc1 is deleted. Notably, treatment of adult mice with rapamycin, which inhibits MTOR, reverses the phenotypes. These data reveal novel functions of MTOR signaling in regulating PV expression and FS properties, which may contribute to TSC neuropsychiatric symptoms. Moreover, they suggest that CINs can exhibit properties intermediate between those classically associated with PV+ or SST+ CINs, which may be dynamically regulated by the MTOR signaling.

DOI: https://doi.org/10.1038/s41467-019-12962-4
Immunity. 2019 Oct 17. pii: S1074-7613(19)30418-2. [Epub ahead of print]

Amino Acids License Kinase mTORC1 Activity and Treg Cell Function via Small G Proteins Rag and Rheb.

Hao Shi, Nicole M Chapman, Jing Wen, Cliff Guy, Lingyun Long, Yogesh Dhungana, Sherri Rankin, Stephane Pelletier, Peter Vogel, Hong Wang, Junmin Peng, Kun-Liang Guan, Hongbo Chi.

  Regulatory T (Treg) cells are critical mediators of immune tolerance whose activity depends upon T cell receptor (TCR) and mTORC1 kinase signaling, but the mechanisms that dictate functional activation of these pathways are incompletely understood. Here, we showed that amino acids license Treg cell function by priming and sustaining TCR-induced mTORC1 activity. mTORC1 activation was induced by amino acids, especially arginine and leucine, accompanied by the dynamic lysosomal localization of the mTOR and Tsc complexes. Rag and Rheb GTPases were central regulators of amino acid-dependent mTORC1 activation in effector Treg (eTreg) cells. Mice bearing RagA-RagB- or Rheb1-Rheb2-deficient Treg cells developed a fatal autoimmune disease and had reduced eTreg cell accumulation and function. RagA-RagB regulated mitochondrial and lysosomal fitness, while Rheb1-Rheb2 enforced eTreg cell suppressive gene signature. Together, these findings reveal a crucial requirement of amino acid signaling for licensing and sustaining mTORC1 activation and functional programming of Treg cells.

Keywords:  RagA; RagB; Rheb; Treg cells; amino acids; autoimmunity; eTreg cells; mTOR; metabolism

DOI:  https://doi.org/10.1016/j.immuni.2019.10.001
Cancers (Basel). 2019 Oct 10. pii: E1525. [Epub ahead of print]11(10):

Revising PTEN in the Era of Immunotherapy: New Perspectives for an Old Story.

Geny Piro, Carmine Carbone, Luisa Carbognin, Sara Pilotto, Chiara Ciccarese, Roberto Iacovelli, Michele Milella, Emilio Bria, Giampaolo Tortora.

  Immunotherapy has emerged as the new therapeutic frontier of cancer treatment, showing enormous survival benefits in multiple tumor diseases. Although undeniable success has been observed in clinical trials, not all patients respond to treatment. Different concurrent conditions can attenuate or completely abrogate the usefulness of immunotherapy due to the activation of several escape mechanisms. Indeed, the tumor microenvironment has an almost full immunosuppressive profile, creating an obstacle to therapeutic treatment. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) governs a plethora of cellular processes, including maintenance of genomic stability, cell survival/apoptosis, migration, and metabolism. The repertoire of PTEN functions has recently been expanded to include regulation of the tumor microenvironment and immune system, leading to a drastic reevaluation of the canonical paradigm of PTEN action with new potential implications for immunotherapy-based approaches. Understanding the implication of PTEN in cancer immunoediting and immune evasion is crucial to develop new cancer intervention strategies. Recent evidence has shown a double context-dependent role of PTEN in anticancer immunity. Here we summarize the current knowledge of PTEN's role at a crossroads between tumor and immune compartments, highlighting the most recent findings that are likely to change future clinical practice.

Keywords:  PTEN; immunosuppression; immunotherapy; regulatory T cells

DOI:  https://doi.org/10.3390/cancers11101525
Int J Mol Sci. 2019 Oct 10. pii: E5007. [Epub ahead of print]20(20):

Insulin Receptor Trafficking: Consequences for Insulin Sensitivity and Diabetes.

Yang Chen, Lili Huang, Xinzhou Qi, Chen Chen.

  Insulin receptor (INSR) has been extensively studied in the area of cell proliferation and energy metabolism. Impaired INSR activities lead to insulin resistance, the key factor in the pathology of metabolic disorders including type 2 diabetes mellitus (T2DM). The mainstream opinion is that insulin resistance begins at a post-receptor level. The role of INSR activities and trafficking in insulin resistance pathogenesis has been largely ignored. Ligand-activated INSR is internalized and trafficked to early endosome (EE), where INSR is dephosphorylated and sorted. INSR can be subsequently conducted to lysosome for degradation or recycled back to the plasma membrane. The metabolic fate of INSR in cellular events implies the profound influence of INSR on insulin signaling pathways. Disruption of INSR-coupled activities has been identified in a wide range of insulin resistance-related diseases such as T2DM. Accumulating evidence suggests that alterations in INSR trafficking may lead to severe insulin resistance. However, there is very little understanding of how altered INSR activities undermine complex signaling pathways to the development of insulin resistance and T2DM. Here, we focus this review on summarizing previous findings on the molecular pathways of INSR trafficking in normal and diseased states. Through this review, we provide insights into the mechanistic role of INSR intracellular processes and activities in the development of insulin resistance and diabetes.

Keywords:  endocytosis; insulin receptor; insulin resistance; recycling; trafficking

DOI:  https://doi.org/10.3390/ijms20205007
Theranostics. 2019 ;9(23): 7003-7015

FKBP4 connects mTORC2 and PI3K to activate the PDK1/Akt-dependent cell proliferation signaling in breast cancer.

Alain Mangé, Etienne Coyaud, Caroline Desmetz, Estelle Laurent, Benoit Béganton, Peter Coopman, Brian Raught, Jérôme Solassol.

  Purpose: Among the FKBP family members, FKBP4 has been described to have a potential role in tumorigenesis, and as a putative tissue marker. We previously showed that FKBP4, an HSP90-associated co-chaperone, can elicit immune response as a tumor-specific antigen, and are overexpressed in breast cancer. Experimental design: In this study, we examined how loss of FKBP4 affect breast cancer progression and exploited protein interactomics to gain mechanistic insight into this process. Results: We found that FKBP4 expression is associated with breast cancer progression and prognosis, especially of ER-negative breast cancer. Furthermore, FKBP4 depletion specifically reduces cell growth and proliferation of triple negative breast cancer cell model and xenograft tumor model. Using specific protein interactome strategy by BirA proximity-dependent biotin identification, we demonstrated that FKBP4 is a novel PI3K-Akt-mTOR proximal interacting protein. Conclusion: Our results suggest that FKBP4 interacts with PI3K and can enhance Akt activation through PDK1 and mTORC2.

Keywords:  AKT; BioID; FKBP4; FKBP52; breast cancer; mTOR

DOI:  https://doi.org/10.7150/thno.35561
J Immunol. 2019 Nov 01. pii: ji1900395. [Epub ahead of print]

Folliculin Interacting Protein 1 Maintains Metabolic Homeostasis during B Cell Development by Modulating AMPK, mTORC1, and TFE3.

Julita A Ramírez, Terri Iwata, Heon Park, Mark Tsang, Janella Kang, Katy Cui, Winnie Kwong, Richard G James, Masaya Baba, Laura S Schmidt, Brian M Iritani.

Folliculin interacting protein 1 (Fnip1) is a cytoplasmic protein originally discovered through its interaction with the master metabolic sensor 5' AMP-activated protein kinase (AMPK) and Folliculin, a protein mutated in individuals with Birt-Hogg-Dubé Syndrome. In response to low energy, AMPK stimulates catabolic pathways such as autophagy to enhance energy production while inhibiting anabolic pathways regulated by the mechanistic target of rapamycin complex 1 (mTORC1). We previously found that constitutive disruption of Fnip1 in mice resulted in a lack of peripheral B cells because of a block in B cell development at the pre-B cell stage. Both AMPK and mTORC1 were activated in Fnip1-deficient B cell progenitors. In this study, we found inappropriate mTOR localization at the lysosome under nutrient-depleted conditions. Ex vivo lysine or arginine depletion resulted in increased apoptosis. Genetic inhibition of AMPK, inhibition of mTORC1, or restoration of cell viability with a Bcl-xL transgene failed to rescue B cell development in Fnip1-deficient mice. Fnip1-deficient B cell progenitors exhibited increased nuclear localization of transcription factor binding to IgHM enhancer 3 (TFE3) in developing B cells, which correlated with an increased expression of TFE3-target genes, increased lysosome numbers and function, and increased autophagic flux. These results indicate that Fnip1 modulates autophagy and energy response pathways in part through the regulation of AMPK, mTORC1, and TFE3 in B cell progenitors.

DOI: https://doi.org/10.4049/jimmunol.1900395
Nat Rev Cancer. 2019 Oct 30.

Controversies around epithelial-mesenchymal plasticity in cancer metastasis.

Elizabeth D Williams, Dingcheng Gao, Andrew Redfern, Erik W Thompson.

Experimental evidence accumulated over decades has implicated epithelial-mesenchymal plasticity (EMP), which collectively encompasses epithelial-mesenchymal transition and the reverse process of mesenchymal-epithelial transition, in tumour metastasis, cancer stem cell generation and maintenance, and therapeutic resistance. However, the dynamic nature of EMP processes, the apparent need to reverse mesenchymal changes for the development of macrometastases and the likelihood that only minor cancer cell subpopulations exhibit EMP at any one time have made such evidence difficult to accrue in the clinical setting. In this Perspectives article, we outline the existing preclinical and clinical evidence for EMP and reflect on recent controversies, including the failure of initial lineage-tracing experiments to confirm a major role for EMP in dissemination, and discuss accumulating data suggesting that epithelial features and/or a hybrid epithelial-mesenchymal phenotype are important in metastasis. We also highlight strategies to address the complexities of therapeutically targeting the EMP process that give consideration to its spatially and temporally divergent roles in metastasis, with the view that this will yield a potent and broad class of therapeutic agents.

DOI: https://doi.org/10.1038/s41568-019-0213-x
FASEB J. 2019 Oct 29. fj201900396RR

Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.

Fatima Mohsen Mroueh, Mohamed Noureldein, Youssef H Zeidan, Suzan Boutary, Sara Abou Merhi Irani, Stéphanie Eid, Mary Haddad, Rasha Barakat, Frederic Harb, Joseph Costantine, Rouwaida Kanj, Erik-André Sauleau, Allal Ouhtit, Sami T Azar, Ali H Eid, Assaad A Eid.

  Cancer was recently annexed to diabetic complications. Furthermore, recent studies suggest that cancer can increase the risk of diabetes. Consequently, diabetes and cancer share many risk factors, but the cellular and molecular pathways correlating diabetes and colon and rectal cancer (CRC) remain far from understood. In this study, we assess the effect of hyperglycemia on cancer cell aggressiveness in human colon epithelial adenocarcinoma cells in vitro and in an experimental animal model of CRC. Our results show that Nox (NADPH oxidase enzyme) 4-induced reactive oxygen species (ROS) production is deregulated in both diabetes and CRC. This is paralleled by inactivation of the AMPK and activation of the mammalian target of rapamycin (mTOR) C1 signaling pathways, resulting in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) accumulation, induction of DNA damage, and exacerbation of cancer cell aggressiveness, thus contributing to the genomic instability and predisposition to increased tumorigenesis in the diabetic milieu. Pharmacologic activation of AMPK, inhibition of mTORC1, or blockade of Nox4 reduce ROS production, restore the homeostatic signaling of 8-oxoguanine DNA glycosylase/8-oxodG, and lessen the progression of CRC malignancy in a diabetic milieu. Taken together, our results identify the AMPK/mTORC1/Nox4 signaling axis as a molecular switch correlating diabetes and CRC. Modulating this pathway may be a strategic target of therapeutic potential aimed at reversing or slowing the progression of CRC in patients with or without diabetes.-Mroueh, F. M., Noureldein, M., Zeidan, Y. H., Boutary, S., Irani, S. A. M., Eid, S., Haddad, M., Barakat, R., Harb, F., Costantine, J., Kanj, R., Sauleau, E.-A., Ouhtit, A., Azar, S. T., Eid, A. H., Eid, A. A. Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.

Keywords:  DNA damage; NADPH oxidases; colorectal cancer; mTORC1

DOI:  https://doi.org/10.1096/fj.201900396RR
PLoS Genet. 2019 Oct;15(10): e1008451

The comprehensive role of E-cadherin in maintaining prostatic epithelial integrity during oncogenic transformation and tumor progression.

Adam Olson, Vien Le, Joseph Aldahl, Eun-Jeong Yu, Erika Hooker, Yongfeng He, Dong-Hong Lee, Won Kyung Kim, Robert D Cardiff, Joseph Geradts, Zijie Sun.

E-cadherin complexes with the actin cytoskeleton via cytoplasmic catenins and maintains the functional characteristics and integrity of the epithelia in normal epithelial tissues. Lost expression of E-cadherin disrupts this complex resulting in loss of cell polarity, epithelial denudation and increased epithelial permeability in a variety of tissues. Decreased expression of E-cadherin has also been observed in invasive and metastatic human tumors. In this study, we investigated the effect of E-cadherin loss in prostatic epithelium using newly developed genetically engineered mouse models. Deletion of E-cadherin in prostatic luminal epithelial cells with modified probasin promoter driven Cre (PB-Cre4) induced the development of mouse prostatic intraepithelial neoplasia (PIN). An increase in levels of cytoplasmic and nuclear β-catenin appeared in E-cadherin deleted atypical cells within PIN lesions. Using various experimental approaches, we further demonstrated that the knockdown of E-cadherin expression elevated free cytoplasmic and nuclear β-catenin and enhanced androgen-induced transcription and cell growth. Intriguingly, pathological changes representing prostatic epithelial cell denudation and increased apoptosis accompanied the above PIN lesions. The essential role of E-cadherin in maintaining prostatic epithelial integrity and organization was further demonstrated using organoid culture approaches. To directly assess the role of loss of E-cadherin in prostate tumor progression, we generated a new mouse model with bigenic Cdh1 and Pten deletion in prostate epithelium. Early onset, aggressive tumor phenotypes presented in the compound mice. Strikingly, goblet cell metaplasia was observed, intermixed within prostatic tumor lesions of the compound mice. This study provides multiple lines of novel evidence demonstrating a comprehensive role of E-cadherin in maintaining epithelial integrity during the course of prostate oncogenic transformation, tumor initiation and progression.

DOI: https://doi.org/10.1371/journal.pgen.1008451
Cells. 2019 Oct 29. pii: E1337. [Epub ahead of print]8(11):

Akt1 and Akt2 Isoforms Play Distinct Roles in Regulating the Development of Inflammation and Fibrosis Associated with Alcoholic Liver Disease.

Karina Reyes-Gordillo, Ruchi Shah, Jaime Arellanes-Robledo, Ying Cheng, Joseph Ibrahim, Pamela L Tuma.

  Akt kinase isoforms (Akt1, Akt2, and Akt3) have generally been thought to play overlapping roles in phosphoinositide 3-kinase (PI3K)-mediated-signaling. However, recent studies have suggested that they display isoform-specific roles in muscle and fat. To determine whether such isoform-specificity is observed with respect to alcoholic liver disease (ALD) progression, we examined the role of Akt1, Akt2, and Akt3 in hepatic inflammation, and pro-fibrogenic proliferation and migration using Kupffer cells, hepatic stellate cells (HSC), and hepatocytes in an ethanol and lipopolysaccharide (LPS)-induced two-hit model in vitro and in vivo. We determined that siRNA-directed silencing of Akt2, but not Akt1, significantly suppressed cell inflammatory markers in HSC and Kupffer cells. Although both Akt1 and Akt2 inhibited cell proliferation in HSC, only Akt2 inhibited cell migration. Both Akt1 and Akt2, but not Akt3, inhibited fibrogenesis in hepatocytes and HSC. In addition, our in vivo results show that administration of chronic ethanol, binge ethanol and LPS (EBL) in wild-type C57BL/6 mice activated all three Akt isoforms with concomitant increases in activated forms of phosphoinositide dependent kinase-1 (PDK1), mammalian target-of-rapamycin complex 2 (mTORC2), and PI3K, resulting in upregulation in expression of inflammatory, proliferative, and fibrogenic genes. Moreover, pharmacological blocking of Akt2, but not Akt1, inhibited EBL-induced inflammation while blocking of both Akt1 and Akt2 inhibited pro-fibrogenic marker expression and progression of fibrosis. Our findings indicate that Akt isoforms play unique roles in inflammation, cell proliferation, migration, and fibrogenesis during EBL-induced liver injury. Thus, close attention must be paid when targeting all Akt isoforms as a therapeutic intervention.

Keywords:  Akt isoforms; Akt1; Akt2; Akt3; alcoholic liver disease; inflammation; liver fibrosis; migration; proliferation

DOI:  https://doi.org/10.3390/cells8111337
Nat Mater. 2019 Oct 28.

Stopping transformed cancer cell growth by rigidity sensing.

Bo Yang, Haguy Wolfenson, Vin Yee Chung, Naotaka Nakazawa, Shuaimin Liu, Junqiang Hu, Ruby Yun-Ju Huang, Michael P Sheetz.

A common feature of cancer cells is the alteration of kinases and biochemical signalling pathways enabling transformed growth on soft matrices, whereas cytoskeletal protein alterations are thought to be a secondary issue. However, we report here that cancer cells from different tissues can be toggled between transformed and rigidity-dependent growth states by the absence or presence of mechanosensory modules, respectively. In various cancer lines from different tissues, cells had over tenfold fewer rigidity-sensing contractions compared with normal cells from the same tissues. Restoring normal levels of cytoskeletal proteins, including tropomyosins, restored rigidity sensing and rigidity-dependent growth. Further depletion of other rigidity sensor proteins, including myosin IIA, restored transformed growth and blocked sensing. In addition, restoration of rigidity sensing to cancer cells inhibited tumour formation and changed expression patterns. Thus, the depletion of rigidity-sensing modules through alterations in cytoskeletal protein levels enables cancer cell growth on soft surfaces, which is an enabling factor for cancer progression.

DOI: https://doi.org/10.1038/s41563-019-0507-0
Mol Metab. 2019 Nov;pii: S2212-8778(19)30608-8. [Epub ahead of print]29 65-75

Temporal patterns of lipolytic regulators in adipose tissue after acute growth hormone exposure in human subjects: A randomized controlled crossover trial.

Astrid Johannesson Hjelholt, Kevin Y Lee, Mai Christiansen Arlien-Søborg, Steen Bønløkke Pedersen, John J Kopchick, Vishwajeet Puri, Niels Jessen, Jens Otto L Jørgensen.

  OBJECTIVE: Growth hormone (GH) stimulates lipolysis, but the underlying mechanisms remain incompletely understood. We examined the effect of GH on the expression of lipolytic regulators in adipose tissue (AT).METHODS: In a randomized, placebo-controlled, cross-over study, nine men were examined after injection of 1) a GH bolus and 2) a GH-receptor antagonist (pegvisomant) followed by four AT biopsies. In a second study, eight men were examined in a 2 × 2 factorial design including GH infusion and 36-h fasting with AT biopsies obtained during a basal period and a hyperinsulinemic-euglycemic clamp. Expression of GH-signaling intermediates and lipolytic regulators were studied by PCR and western blotting. In addition, mechanistic experiments in mouse models and 3T3-L1 adipocytes were performed.
RESULTS: The GH bolus increased circulating free fatty acids (p < 0.0001) together with phosphorylation of signal transducer and activator of transcription 5 (STAT5) (p < 0.0001) and mRNA expression of the STAT5-dependent genes cytokine-inducible SH2-containing protein (CISH) and IGF-1 in AT. This was accompanied by suppressed mRNA expression of G0/G1 switch gene 2 (G0S2) (p = 0.007) and fat specific protein 27 (FSP27) (p = 0.002) and upregulation of phosphatase and tensin homolog (PTEN) mRNA expression (p = 0.03). Suppression of G0S2 was also observed in humans after GH infusion and fasting, as well as in GH transgene mice, and in vitro studies suggested MEK-PPARγ signaling to be involved.
CONCLUSIONS: GH-induced lipolysis in human subjects in vivo is linked to downregulation of G0S2 and FSP27 and upregulation of PTEN in AT. Mechanistically, in vitro data suggest that GH acts via MEK to suppress PPARγ-dependent transcription of G0S2. ClinicalTrials.govNCT02782221 and NCT01209429.

Keywords:  FSP27; G0S2; Growth hormone; Lipolysis; PTEN

DOI:  https://doi.org/10.1016/j.molmet.2019.08.013
Science. 2019 Oct 31. pii: eaax7890. [Epub ahead of print]

In vitro culture of cynomolgus monkey embryos beyond early gastrulation.

Huaixiao Ma, Jinglei Zhai, Haifeng Wan, Xiangxiang Jiang, Xiaoxiao Wang, Lin Wang, Yunlong Xiang, Xiechao He, Zhen-Ao Zhao, Bo Zhao, Ping Zheng, Lei Li, Hongmei Wang.

Gastrulation is a key event in embryonic development when the germ layers are specified and the basic animal body plan is established. The complexities of primate gastrulation remain a mystery due to the difficulties in accessing primate embryos at this stage. Here, we report the establishment of an in vitro culture (IVC) system which supports the continuous development of cynomolgus monkey blastocysts beyond early gastrulation and to 20 days post fertilization. The IVC embryos highly recapitulated the key events of in vivo early post-implantation development, including segregation of the epiblast and hypoblast, formation of the amniotic and yolk sac cavities, appearance of the primordial germ cells, and establishment of the anterior-posterior axis. Single-cell RNA-seq analyses of the IVC primate embryos provide information about lineage specification during primate early post-implantation development. This system provides a platform to explore the characteristics and mechanisms of early post-implantation embryogenesis in primates with possible conservation of cell movements and lineages in human embryogenesis.

DOI: https://doi.org/10.1126/science.aax7890
Nat Commun. 2019 Nov 01. 10(1): 5016

Microenvironmental IL1β promotes breast cancer metastatic colonisation in the bone via activation of Wnt signalling.

Rachel Eyre, Denis G Alférez, Angélica Santiago-Gómez, Kath Spence, James C McConnell, Claire Hart, Bruno M Simões, Diane Lefley, Claudia Tulotta, Joanna Storer, Austin Gurney, Noel Clarke, Mick Brown, Sacha J Howell, Andrew H Sims, Gillian Farnie, Penelope D Ottewell, Robert B Clarke.

Dissemination of tumour cells to the bone marrow is an early event in breast cancer, however cells may lie dormant for many years before bone metastases develop. Treatment for bone metastases is not curative, therefore new adjuvant therapies which prevent the colonisation of disseminated cells into metastatic lesions are required. There is evidence that cancer stem cells (CSCs) within breast tumours are capable of metastasis, but the mechanism by which these colonise bone is unknown. Here, we establish that bone marrow-derived IL1β stimulates breast cancer cell colonisation in the bone by inducing intracellular NFkB and CREB signalling in breast cancer cells, leading to autocrine Wnt signalling and CSC colony formation. Importantly, we show that inhibition of this pathway prevents both CSC colony formation in the bone environment, and bone metastasis. These findings establish that targeting IL1β-NFKB/CREB-Wnt signalling should be considered for adjuvant therapy to prevent breast cancer bone metastasis.

DOI: https://doi.org/10.1038/s41467-019-12807-0
FASEB J. 2019 Oct 26. fj201901705R

Tackling MARCKS-PIP3 circuit attenuates fibroblast activation and fibrosis progression.

David C Yang, Ji-Min Li, Jihao Xu, Justin Oldham, Sem H Phan, Jerold A Last, Reen Wu, Ching-Hsien Chen.

  Targeting activated fibroblasts, including myofibroblast differentiation, has emerged as a key therapeutic strategy in patients with idiopathic pulmonary fibrosis (IPF). However, there is no available therapy capable of selectively eradicating myofibroblasts or limiting their genesis. Through an integrative analysis of the regulator genes that are responsible for the activation of IPF fibroblasts, we noticed the phosphatidylinositol 4,5-bisphosphate (PIP2)-binding protein, myristoylated alanine-rich C-kinase substrate (MARCKS), as a potential target molecule for IPF. Herein, we have employed a 25-mer novel peptide, MARCKS phosphorylation site domain sequence (MPS), to determine if MARCKS inhibition reduces pulmonary fibrosis through the inactivation of PI3K/protein kinase B (AKT) signaling in fibroblast cells. We first observed that higher levels of MARCKS phosphorylation and the myofibroblast marker α-smooth muscle actin (α-SMA) were notably overexpressed in all tested IPF lung tissues and fibroblast cells. Treatment with the MPS peptide suppressed levels of MARCKS phosphorylation in primary IPF fibroblasts. A kinetic assay confirmed that this peptide binds to phospholipids, particularly PIP2, with a dissociation constant of 17.64 nM. As expected, a decrease of phosphatidylinositol (3,4,5)-trisphosphate pools and AKT activity occurred in MPS-treated IPF fibroblast cells. MPS peptide was demonstrated to impair cell proliferation, invasion, and migration in multiple IPF fibroblast cells in vitro as well as to reduce pulmonary fibrosis in bleomycin-treated mice in vivo. Surprisingly, we found that MPS peptide decreases α-SMA expression and synergistically interacts with nintedanib treatment in IPF fibroblasts. Our data suggest MARCKS as a druggable target in pulmonary fibrosis and also provide a promising antifibrotic agent that may lead to effective IPF treatments.-Yang, D. C., Li, J.-M., Xu, J., Oldham, J., Phan, S. H., Last, J. A., Wu, R., Chen, C.-H. Tackling MARCKS-PIP3 circuit attenuates fibroblast activation and fibrosis progression.

Keywords:  AKT signaling; drug efficacy; nintedanib; phospholipids; pulmonary fibrosis

DOI:  https://doi.org/10.1096/fj.201901705R
Nat Commun. 2019 Nov 01. 10(1): 5011

Essentiality of fatty acid synthase in the 2D to anchorage-independent growth transition in transforming cells.

Maria J Bueno, Veronica Jimenez-Renard, Sara Samino, Jordi Capellades, Alejandra Junza, María Luz López-Rodríguez, Javier Garcia-Carceles, Irene Lopez-Fabuel, Juan P Bolaños, Navdeep S Chandel, Oscar Yanes, Ramon Colomer, Miguel Quintela-Fandino.

Upregulation of fatty acid synthase (FASN) is a common event in cancer, although its mechanistic and potential therapeutic roles are not completely understood. In this study, we establish a key role of FASN during transformation. FASN is required for eliciting the anaplerotic shift of the Krebs cycle observed in cancer cells. However, its main role is to consume acetyl-CoA, which unlocks isocitrate dehydrogenase (IDH)-dependent reductive carboxylation, producing the reductive power necessary to quench reactive oxygen species (ROS) originated during the switch from two-dimensional (2D) to three-dimensional (3D) growth (a necessary hallmark of cancer). Upregulation of FASN elicits the 2D-to-3D switch; however, FASN's synthetic product palmitate is dispensable for this process since cells satisfy their fatty acid requirements from the media. In vivo, genetic deletion or pharmacologic inhibition of FASN before oncogenic activation prevents tumor development and invasive growth. These results render FASN as a potential target for cancer prevention studies.

DOI: https://doi.org/10.1038/s41467-019-13028-1
Angiogenesis. 2019 Oct 26.

Pathological features of vessel co-option versus sprouting angiogenesis.

Emily Latacz, Elisabetta Caspani, Raymond Barnhill, Claire Lugassy, Cornelis Verhoef, Dirk Grünhagen, Steven Van Laere, Carlos Fernández Moro, Marco Gerling, Marie Dirix, Luc Y Dirix, Peter B Vermeulen.

  Cancer cells can use existing blood vessels to acquire a vasculature. This process is termed 'vessel co-option'. Vessel co-option is an alternative to the growth of new blood vessels, or angiogenesis, and is adopted by a wide range of human tumour types growing within numerous tissues. A complementary aspect of this process is extravascular migratory tumour spread using the co-opted blood vessels as a trail. Vessel co-opting tumours can be discriminated from angiogenic tumours by specific morphological features. These features give rise to distinct histopathological growth patterns that reflect the interaction of cancer cells with the microenvironment of the organ in which they thrive. We will discuss the histopathological growth patterns of vessel co-option in the brain, the liver and the lungs. The review will also highlight evidence for the potential clinical value of the histopathological growth patterns of cancer. Vessel co-option can affect patient outcomes and resistance to cancer treatment. Insight into the biological drivers of this process of tumour vascularization will yield novel therapeutic strategies.

Keywords:  Angiogenesis; Angiotropism; Extravascular migratory metastasis; Histopathological growth patterns; Metastasis; Pericytic mimicry; Tumour microenvironment; Vessel co-option

DOI:  https://doi.org/10.1007/s10456-019-09690-0