scholarly journals Mammary Tumorigenesis and Metastasis Caused by Overexpression of Insulin Receptor Substrate 1 (IRS-1) or IRS-2

2006 ◽  
Vol 26 (24) ◽  
pp. 9302-9314 ◽  
Author(s):  
Robert K. Dearth ◽  
Xiaojiang Cui ◽  
Hyun-Jung Kim ◽  
Isere Kuiatse ◽  
Nicole A. Lawrence ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Kinase Activity ◽  
Mammary Tumorigenesis ◽  
Poor Patient ◽  
Insulin Receptor Substrates ◽  
Mammary Hyperplasia ◽  
Patient Prognosis ◽  
Insulin Like Growth Factors

ABSTRACT Insulin receptor substrates (IRSs) are signaling adaptors that play a major role in the metabolic and mitogenic actions of insulin and insulin-like growth factors. Reports have recently noted increased levels, or activity, of IRSs in many human cancers, and some have linked this to poor patient prognosis. We found that overexpressed IRS-1 was constitutively phosphorylated in vitro and in vivo and that transgenic mice overexpressing IRS-1 or IRS-2 in the mammary gland showed progressive mammary hyperplasia, tumorigenesis, and metastasis. Tumors showed extensive squamous differentiation, a phenotype commonly seen with activation of the canonical β-catenin signaling pathway. Consistent with this, IRSs were found to bind β-catenin in vitro and in vivo. IRS-induced tumorigenesis is unique, given that the IRSs are signaling adaptors with no intrinsic kinase activity, and this supports a growing literature indicating a role for IRSs in cancer. This study defines IRSs as oncogene proteins in vivo and provides new models to develop inhibitors against IRSs for anticancer therapy.

scholarly journals Fascin1 empowers YAP mechanotransduction and promotes cholangiocarcinoma development

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Arianna Pocaterra ◽  
Gloria Scattolin ◽  
Patrizia Romani ◽  
Cindy Ament ◽  
Silvia Ribback ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Control Cell ◽  
Actin Dynamics ◽  
Cell Behavior ◽  
Mechanical Forces ◽  
Poor Patient ◽  
Cholangiocarcinoma Cell ◽  
Patient Prognosis

AbstractMechanical forces control cell behavior, including cancer progression. Cells sense forces through actomyosin to activate YAP. However, the regulators of F-actin dynamics playing relevant roles during mechanostransduction in vitro and in vivo remain poorly characterized. Here we identify the Fascin1 F-actin bundling protein as a factor that sustains YAP activation in response to ECM mechanical cues. This is conserved in the mouse liver, where Fascin1 regulates YAP-dependent phenotypes, and in human cholangiocarcinoma cell lines. Moreover, this is relevant for liver tumorigenesis, because Fascin1 is required in the AKT/NICD cholangiocarcinogenesis model and it is sufficient, together with AKT, to induce cholangiocellular lesions in mice, recapitulating genetic YAP requirements. In support of these findings, Fascin1 expression in human intrahepatic cholangiocarcinomas strongly correlates with poor patient prognosis. We propose that Fascin1 represents a pro-oncogenic mechanism that can be exploited during intrahepatic cholangiocarcinoma development to overcome a mechanical tumor-suppressive environment.

scholarly journals The effect of fasting on the activation in vivo of the insulin receptor kinase

1990 ◽  
Vol 265 (3) ◽  
pp. 887-890 ◽  
Author(s):  
I Contreras ◽  
G L Dohm ◽  
S Abdallah ◽  
J A Wells ◽  
N Mooney ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Insulin Receptor ◽  
Receptor Tyrosine Kinase ◽  
Kinase Activity ◽  
Serum Glucose ◽  
Tyrosine Kinase Activity ◽  
Insulin Receptor Tyrosine Kinase ◽  
And Control

Fasting causes insulin resistance in liver and fat, and increases insulin sensitivity in muscle. We studied the response in vitro and in vivo to insulin of the insulin receptor tyrosine kinase in muscle and liver from 72 h fasted and control rats. Insulin was injected intraperitoneally together with glucose, and blood and tissue samples were obtained 0, 5, 15 and 30 min later. Basal serum glucose and insulin levels were significantly higher in control than in fasting rats. Serum glucose rose to approximately 300 mg/dl at 5 min and then progressively declined without hypoglycaemia. Receptors were prepared from whole tissue by wheat germ lectin affinity chromatography. 125I-insulin binding to purified receptors was increased by fasting in both muscle (18%) and liver (50%). In untreated fasting and control animals, muscle and liver insulin receptor tyrosine kinase activity was stimulated to similar levels by insulin added in vitro. With only insulin treatment in vivo, muscle receptor tyrosine kinase behaved similarly in fasting and control animals with maximal activation at 15 min post injection. In liver, insulin in vivo stimulated receptor tyrosine kinase activity maximally at 5 min post injection in both fasting and control, but in fasting animals the treatment in vivo caused a significantly larger and more prolonged activation of the enzymic activity, possibly due to a decrease in the rate of dephosphorylation and deactivation of the beta subunits.

scholarly journals ELK1 Promotes Epithelial-Mesenchymal Transition and the Progression of Lung Adenocarcinoma by Upregulating B7-H3

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Ting-ting Yu ◽  
Tao Zhang ◽  
Fei Su ◽  
Ying-long Li ◽  
Li Shan ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Epithelial To Mesenchymal Transition ◽  
Epithelial Mesenchymal Transition ◽  
Transcriptional Regulator ◽  
Mesenchymal Transition ◽  
Poor Patient ◽  
Patient Prognosis

In previous studies, we found that B7 homolog 3 (B7-H3) was highly expressed in lung adenocarcinoma (LUAD) and promoted epithelial-to-mesenchymal transition (EMT) of LUAD cells. However, the underlying molecular mechanism is unclear. This study is aimed at evaluating the role of Ets-like protein 1 (ELK1) as a transcriptional regulator of B7-H3 for mediating the development and progression of LUAD in vitro and in vivo. We confirmed that ELK1 is highly expressed in LUAD and is associated with poor patient prognosis. ELK1 was found to promote proliferation, invasion, migration, and EMT of LUAD cells through in vivo and in vitro experiments. In terms of mechanism, ELK1 binds to the B7-H3 promoter region and induces the upregulation of B7-H3 in LUAD. Our data suggest that ELK1 plays an important role in the development of LUAD and could be used as a prognostic marker and therapeutic target for LUAD.

scholarly journals Connexin 43 confers chemoresistance through activating PI3K

2020 ◽  
Author(s):  
Kevin J Pridham ◽  
Farah Shah ◽  
Kevin L Sheng ◽  
Sujuan Guo ◽  
Min Liu ◽  
...  
Keyword(s):  
Connexin 43 ◽  
Carboxyl Terminus ◽  
Phosphatidylinositol 3 Kinase ◽  
Poor Patient ◽  
Junction Protein ◽  
Gap Junction Protein ◽  
Targeting Peptide ◽  
Patient Prognosis

ABSTRACTCircumventing chemoresistance is crucial for effectively treating glioblastoma due to limited therapeutic options. The gap junction protein connexin 43 (Cx43) renders glioblastoma resistant to the frontline chemotherapy temozolomide; however, targeting Cx43 is difficult because mechanisms underlying Cx43-mediated chemoresistance remain elusive. Here we show that Cx43, but not other connexins, is highly expressed in glioblastoma and strongly correlates with poor patient prognosis and chemoresistance, making Cx43 the prime therapeutic target among all connexins. The intracellular carboxyl terminus of Cx43 binds to phosphatidylinositol 3-kinase (PI3K) catalytic subunit β (PIK3CB, also called PI3Kβ or p110β), thereby activating PI3K signaling independent of Cx43-channels and subsequently inducing temozolomide resistance. A combination of αCT1, a Cx43-targeting peptide inhibitor, and PIK3CB-selective inhibitors restores temozolomide sensitivity in vitro and in vivo. This study not only reveals novel mechanistic insights into chemoresistance in glioblastoma, but also demonstrates that targeting Cx43 and PIK3CB/p110β is an effective approach for overcoming chemoresistance.

scholarly journals Plant Physiology, 2021 Functional redox links between lumen thiol oxidoreductase1 and serine/threonine-protein kinase STN7

2021 ◽  
Author(s):  
Jianghao Wu ◽  
Liwei Rong ◽  
Weijun Lin ◽  
Lingxi Kong ◽  
Dengjie Wei ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Disulfide Bonds ◽  
Kinase Activity ◽  
Light Harvesting ◽  
Photosynthetic Electron Transport ◽  
State Transitions ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii

Abstract In response to changing light quantity and quality, photosynthetic organisms perform state transitions, a process which optimizes photosynthetic yield and mitigates photo-damage. The serine/threonine-protein kinase STN7 phosphorylates the light-harvesting complex of photosystem II (PSII; light-harvesting complex II), which then migrates from PSII to photosystem I (PSI), thereby rebalancing the light excitation energy between the photosystems and restoring the redox poise of the photosynthetic electron transport chain. Two conserved cysteines forming intra- or intermolecular disulfide bonds in the lumenal domain (LD) of STN7 are essential for the kinase activity although it is still unknown how activation of the kinase is regulated. In this study, we show lumen thiol oxidoreductase 1 (LTO1) is co-expressed with STN7 in Arabidopsis (Arabidopsis thaliana) and interacts with the LD of STN7 in vitro and in vivo. LTO1 contains thioredoxin (TRX)-like and vitamin K epoxide reductase domains which are related to the disulfide-bond formation system in bacteria. We further show that the TRX-like domain of LTO1 is able to oxidize the conserved lumenal cysteines of STN7 in vitro. In addition, loss of LTO1 affects the kinase activity of STN7 in Arabidopsis. Based on these results, we propose that LTO1 helps to maintain STN7 in an oxidized active state in state 2 through redox interactions between the lumenal cysteines of STN7 and LTO1.

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