scholarly journals Targeted Deletion of PTEN in Kisspeptin Cells Results in Brain Region- and Sex-Specific Effects on Kisspeptin Expression and Gonadotropin Release

2020 ◽  
Vol 21 (6) ◽  
pp. 2107 ◽  
Author(s):  
Ariel L. Negrón ◽  
Guiqin Yu ◽  
Ulrich Boehm ◽  
Maricedes Acosta-Martínez
Keyword(s):  
Arcuate Nucleus ◽  
Cell Metabolism ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
Targeted Deletion ◽  
Gonadotropin Release ◽  
Tensin Homolog ◽  
Specific Effects ◽  
Periventricular Nucleus ◽  
Specific Deletion

Kisspeptin-expressing neurons in the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC) of the hypothalamus relay hormonal and metabolic information to gonadotropin-releasing hormone neurons, which in turn regulate pituitary and gonadal function. Phosphatase and tensin homolog (PTEN) blocks phosphatidylinositol 3-kinase (PI3K), a signaling pathway utilized by peripheral factors to transmit their signals. However, whether PTEN signaling in kisspeptin neurons helps to integrate peripheral hormonal cues to regulate gonadotropin release is unknown. To address this question, we generated mice with a kisspeptin cell-specific deletion of Pten (Kiss-PTEN KO), and first assessed kisspeptin protein expression and gonadotropin release in these animals. Kiss-PTEN KO mice displayed a profound sex and region-specific kisspeptin neuron hyperthrophy. We detected both kisspeptin neuron hyperthrophy as well as increased kisspeptin fiber densities in the AVPV and ARC of Kiss-PTEN KO females and in the ARC of Kiss-PTEN KO males. Moreover, Kiss-PTEN KO mice showed a reduced gonadotropin release in response to gonadectomy. We also found a hyperactivation of mTOR, a downstream PI3K target and central regulator of cell metabolism, in the AVPV and ARC of Kiss-PTEN KO females but not males. Fasting, known to inhibit hypothalamic kisspeptin expression and luteinizing hormone levels, failed to induce these changes in Kiss-PTEN KO females. We conclude that PTEN signaling regulates kisspeptin protein synthesis in both sexes and that its role as a metabolic signaling molecule in kisspeptin neurons is sex-specific.

scholarly journals Phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog as therapeutic targets in breast cancer

Tumor Biology ◽  
2017 ◽  
Vol 39 (3) ◽  
pp. 101042831769552 ◽  
Author(s):  
Ebubekir Dirican ◽  
Mustafa Akkiprik
Keyword(s):  
Breast Cancer ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Breast Cancer Progression ◽  
Regulatory Subunit ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Kinase Pathway ◽  
Phosphatidylinositol 3

Breast cancer is the most commonly diagnosed cancer among women in Turkey and worldwide. It is considered a heterogeneous disease and has different subtypes. Moreover, breast cancer has different molecular characteristics, behaviors, and responses to treatment. Advances in the understanding of the molecular mechanisms implicated in breast cancer progression have led to the identification of many potential therapeutic gene targets, such as Breast Cancer 1/2, phosphatidylinositol 3-kinase catalytic subunit alpha, and tumor protein 53. The aim of this review is to summarize the roles of phosphatidylinositol 3-kinase regulatory subunit 1 (alpha) (alias p85α) and phosphatase and tensin homolog in breast cancer progression and the molecular mechanisms involved. Phosphatase and tensin homolog is a tumor suppressor gene and protein. Phosphatase and tensin homolog antagonizes the phosphatidylinositol 3-kinase/AKT signaling pathway that plays a key role in cell growth, differentiation, and survival. Loss of phosphatase and tensin homolog expression, detected in about 20%–30% of cases, is known to be one of the most common tumor changes leading to phosphatidylinositol 3-kinase pathway activation in breast cancer. Instead, the regulatory subunit p85α is a significant component of the phosphatidylinositol 3-kinase pathway, and it has been proposed that a reduction in p85α protein would lead to decreased negative regulation of phosphatidylinositol 3-kinase and hyperactivation of the phosphatidylinositol 3-kinase pathway. Phosphatidylinositol 3-kinase regulatory subunit 1 protein has also been reported to be a positive regulator of phosphatase and tensin homolog via the stabilization of this protein. A functional genetic alteration of phosphatidylinositol 3-kinase regulatory subunit 1 that results in reduced p85α protein expression and increased insulin receptor substrate 1 binding would lead to enhanced phosphatidylinositol 3-kinase signaling and hence cancer development. Phosphatidylinositol 3-kinase regulatory subunit 1 underexpression was observed in 61.8% of breast cancer samples. Therefore, expression/alternations of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog genes have crucial roles for breast cancer progression. This review will summarize the biological roles of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog in breast cancer, with an emphasis on recent findings and the potential of phosphatidylinositol 3-kinase regulatory subunit 1 and phosphatase and tensin homolog as a therapeutic target for breast cancer therapy.

scholarly journals BMI1 promotes cardiac fibrosis in ischemia-induced heart failure via the PTEN-PI3K/Akt-mTOR signaling pathway

2019 ◽  
Vol 316 (1) ◽  
pp. H61-H69 ◽  
Author(s):  
Wenbo Yang ◽  
Zhijun Wu ◽  
Ke Yang ◽  
Yanxin Han ◽  
Yanjia Chen ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Mammalian Target Of Rapamycin ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
B Lymphoma ◽  
Tensin Homolog ◽  
And Migration ◽  
Proliferation And Migration

Cardiac fibrosis has been known to play an important role in the etiology of heart failure after myocardial infarction (MI). B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a transcriptional repressor, is important for fibrogenesis in the kidneys. However, the effect of BMI1 on ischemia-induced cardiac fibrosis remains unclear. BMI1 was strongly expressed in the infarct region 1 wk post-MI in mice and was detected by Western blot and histological analyses. Lentivirus-mediated overexpression of BMI1 significantly promoted cardiac fibrosis, worsened cardiac function 4 wk after the intervention in vivo, and enhanced the proliferation and migration capabilities of fibroblasts in vitro , whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in mice 4 wk post-MI in vivo. Furthermore, upregulated BMI1 inhibited phosphatase and tensin homolog (PTEN) expression, enhanced phosphatidylinositol 3-kinase (PI3K) expression, and increased the phosphorylation level of Akt and mammalian target of rapamycin (mTOR) in mice 4 wk after lentiviral infection, which was in accordance with the changes seen in their infarcted myocardial tissues. At the same time, the effects of BMI1 on cardiac fibroblasts were reversed in vitro when these cells were exposed to NVP-BEZ235, a dual-kinase (PI3K/mTOR) inhibitor. In conclusion, BMI1 is associated with cardiac fibrosis and dysfunction after MI by regulating cardiac fibroblast proliferation and migration, and these effects could be partially explained by the regulation of the PTEN-PI3K/Akt-mTOR pathway. NEW & NOTEWORTHY Ischemia-induced B lymphoma Mo-MLV insertion region 1 homolog (BMI1) significantly promoted cardiac fibrosis and worsened cardiac function in vivo, whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in myocardial infarcted mice. BMI1 also enhanced proliferation and migration capabilities of fibroblasts in vitro; these effects were reversed by NVP-BEZ235. Effects of BMI1 on cardiac fibrosis could be partially explained by regulation of the phosphatase and tensin homolog-phosphatidylinositol 3-kinase/Akt-mammalian target of rapamycin pathway.

scholarly journals Molecular Analysis of AFP and HSA Interactions with PTEN Protein

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Mingyue Zhu ◽  
Bo Lin ◽  
Peng Zhou ◽  
Mengsen Li
Keyword(s):  
Molecular Docking ◽  
Molecular Mechanisms ◽  
Docking Study ◽  
Phosphatidylinositol 3 Kinase ◽  
Molecular Docking Study ◽  
Pten Protein ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Significant Homology ◽  
Modeling Data

Human cytoplasmic alpha-fetoprotein (AFP) has been classified as a member of the albuminoid gene family. The protein sequence of AFP has significant homology to that of human serum albumin (HSA), but its biological characteristics are vastly different from HSA. The AFP functions as a regulator in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway, but HSA plays a key role as a transport protein. To probe their molecular mechanisms, we have applied colocalization, coimmunoprecipitation (co-IP), and molecular docking approaches to analyze the differences between AFP and HSA. The data from colocalization and co-IP displayed a strong interaction between AFP and PTEN (phosphatase and tensin homolog), demonstrating that AFP did bind to PTEN, but HSA did not. The molecular docking study further showed that the AFP domains I and III could contact with PTEN.In siliconsubstitutions of AFP binding site residues at position 490M/K and 105L/R corresponding to residues K490 and R105 in HSA resulted in steric clashes with PTEN residues R150 and K46, respectively. These steric clashes may explain the reason why HSA cannot bind to PTEN. Ultimately, the experimental results and the molecular modeling data from the interactions of AFP and HSA with PTEN will help us to identify targets for designing drugs and vaccines against human hepatocellular carcinoma.

scholarly journals Phosphatase and tensin homolog ( PTEN ) mutation can cause activated phosphatidylinositol 3-kinase δ syndrome–like immunodeficiency

2016 ◽  
Vol 138 (6) ◽  
pp. 1672-1680.e10 ◽  
Author(s):  
Yuki Tsujita ◽  
Kanako Mitsui-Sekinaka ◽  
Kohsuke Imai ◽  
Tzu-Wen Yeh ◽  
Noriko Mitsuiki ◽  
...  
Keyword(s):  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
Pten Mutation ◽  
Tensin Homolog ◽  
Phosphatidylinositol 3

scholarly journals Phospholipase C Regulation of Phosphatidylinositol 3,4,5-trisphosphate-mediated Chemotaxis

2007 ◽  
Vol 18 (12) ◽  
pp. 4772-4779 ◽  
Author(s):  
Arjan Kortholt ◽  
Jason S. King ◽  
Ineke Keizer-Gunnink ◽  
Adrian J. Harwood ◽  
Peter J.M. Van Haastert
Keyword(s):  
Phospholipase C ◽  
Leading Edge ◽  
Cell Polarization ◽  
Ph Domain ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
Pi3k Inhibitor Ly294002 ◽  
Tensin Homolog ◽  
Camp Stimulation

Generation of a phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] gradient within the plasma membrane is important for cell polarization and chemotaxis in many eukaryotic cells. The gradient is produced by the combined activity of phosphatidylinositol 3-kinase (PI3K) to increase PI(3,4,5)P3 on the membrane nearest the polarizing signal and PI(3,4,5)P3 dephosphorylation by phosphatase and tensin homolog deleted on chromosome ten (PTEN) elsewhere. Common to both of these enzymes is the lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], which is not only the substrate of PI3K and product of PTEN but also important for membrane binding of PTEN. Consequently, regulation of phospholipase C (PLC) activity, which hydrolyzes PI(4,5)P2, could have important consequences for PI(3,4,5)P3 localization. We investigate the role of PLC in PI(3,4,5)P3-mediated chemotaxis in Dictyostelium. plc-null cells are resistant to the PI3K inhibitor LY294002 and produce little PI(3,4,5)P3 after cAMP stimulation, as monitored by the PI(3,4,5)P3-specific pleckstrin homology (PH)-domain of CRAC (PHCRACGFP). In contrast, PLC overexpression elevates PI(3,4,5)P3 and impairs chemotaxis in a similar way to loss of pten. PI3K localization at the leading edge of plc-null cells is unaltered, but dissociation of PTEN from the membrane is strongly reduced in both gradient and uniform stimulation with cAMP. These results indicate that local activation of PLC can control PTEN localization and suggest a novel mechanism to regulate the internal PI(3,4,5)P3 gradient.

scholarly journals Liver-Specific Deletion of Phosphatase and Tensin Homolog Deleted on Chromosome 10 Significantly Ameliorates Chronic EtOH-Induced Increases in Hepatocellular Damage

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0154152 ◽  
Author(s):  
Colin T. Shearn ◽  
David J. Orlicky ◽  
Rebecca L. McCullough ◽  
Hua Jiang ◽  
Kenneth N. Maclean ◽  
...  
Keyword(s):  
Chromosome 10 ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Hepatocellular Damage ◽  
Specific Deletion

scholarly journals Targeting mTOR in Glioblastoma: Rationale and Preclinical/Clinical Evidence

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Carmen Mecca ◽  
Ileana Giambanco ◽  
Rosario Donato ◽  
Cataldo Arcuri
Keyword(s):  
Therapeutic Strategy ◽  
Molecular Mechanisms ◽  
Clinical Evidence ◽  
Survival Rates ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
Cellular Processes ◽  
Mechanistic Target Of Rapamycin ◽  
Tensin Homolog ◽  
Different Types

The mechanistic target of rapamycin (mTOR) drives several physiologic and pathologic cellular processes and is frequently deregulated in different types of tumors, including glioblastoma (GBM). Despite recent advancements in understanding the molecular mechanisms involved in GBM biology, the survival rates of this tumor are still disappointing, primarily due to the lack of efficacious treatments. The phosphatase and tensin homolog (PTEN)/phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mTOR pathway has emerged as a crucial player in GBM development and progression. However, to date, all the attempts to target this pathway with PI3K, AKT, or mTORC1 inhibitors failed to improve the outcome of patients with GBM. Despite these discouraging results, recent evidence pointed out that the blockade of mTORC2 might provide a useful therapeutic strategy for GBM, with the potential to overcome the limitations that mTORC1 inhibitors have shown so far. In this review, we analyzed the rationale of targeting mTOR in GBM and the available preclinical and clinical evidence supporting the choice of this therapeutic approach, highlighting the different roles of mTORC1 and mTORC2 in GBM biology.

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