scholarly journals Phosphatases: The New Brakes for Cancer Development?

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Qingxiu Zhang ◽  
Francois X. Claret
Keyword(s):  
Cancer Progression ◽  
Pi3k Pathway ◽  
Akt Signaling ◽  
Cancer Development ◽  
Inositol Polyphosphate ◽  
Loss Of Function ◽  
Signaling Axis ◽  
Phosphatase 2A ◽  
Src Homology ◽  
Phosphatase And Tensin Homologue

The phosphatidylinositol 3-kinase (PI3K) pathway plays a pivotal role in the maintenance of processes such as cell growth, proliferation, survival, and metabolism in all cells and tissues. Dysregulation of the PI3K/Akt signaling pathway occurs in patients with many cancers and other disorders. This aberrant activation of PI3K/Akt pathway is primarily caused by loss of function of all negative controllers known as inositol polyphosphate phosphatases and phosphoprotein phosphatases. Recent studies provided evidence of distinct functions of the four main phosphatases—phosphatase and tensin homologue deleted on chromosome 10 (PTEN), Src homology 2-containing inositol 5′-phosphatase (SHIP), inositol polyphosphate 4-phosphatase type II (INPP4B), and protein phosphatase 2A (PP2A)—in different tissues with respect to regulation of cancer development. We will review the structures and functions of PTEN, SHIP, INPP4B, and PP2A phosphatases in suppressing cancer progression and their deregulation in cancer and highlight recent advances in our understanding of the PI3K/Akt signaling axis.

scholarly journals The Human FSGS-Causing ANLN R431C Mutation Induces Dysregulated PI3K/AKT/mTOR/Rac1 Signaling in Podocytes

2018 ◽  
Vol 29 (8) ◽  
pp. 2110-2122 ◽  
Author(s):  
Gentzon Hall ◽  
Brandon M. Lane ◽  
Kamal Khan ◽  
Igor Pediaditakis ◽  
Jianqiu Xiao ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Adaptor Protein ◽  
Pi3k Pathway ◽  
Actin Binding ◽  
Loss Of Function ◽  
Signaling Axis ◽  
Phosphoinositide 3 Kinase

BackgroundWe previously reported that mutations in the anillin (ANLN) gene cause familial forms of FSGS. ANLN is an F-actin binding protein that modulates podocyte cell motility and interacts with the phosphoinositide 3-kinase (PI3K) pathway through the slit diaphragm adaptor protein CD2-associated protein (CD2AP). However, it is unclear how the ANLN mutations cause the FSGS phenotype. We hypothesized that the R431C mutation exerts its pathogenic effects by uncoupling ANLN from CD2AP.MethodsWe conducted in vivo complementation assays in zebrafish to determine the effect of the previously identified missense ANLN variants, ANLNR431C and ANLNG618C during development. We also performed in vitro functional assays using human podocyte cell lines stably expressing wild-type ANLN (ANLNWT) or ANLNR431C.ResultsExperiments in anln-deficient zebrafish embryos showed a loss-of-function effect for each ANLN variant. In human podocyte lines, expression of ANLNR431C increased cell migration, proliferation, and apoptosis. Biochemical characterization of ANLNR431C-expressing podocytes revealed hyperactivation of the PI3K/AKT/mTOR/p70S6K/Rac1 signaling axis and activation of mTOR-driven endoplasmic reticulum stress in ANLNR431C-expressing podocytes. Inhibition of mTOR, GSK-3β, Rac1, or calcineurin ameliorated the effects of ANLNR431C. Additionally, inhibition of the calcineurin/NFAT pathway reduced the expression of endogenous ANLN and mTOR.ConclusionsThe ANLNR431C mutation causes multiple derangements in podocyte function through hyperactivation of PI3K/AKT/mTOR/p70S6K/Rac1 signaling. Our findings suggest that the benefits of calcineurin inhibition in FSGS may be due, in part, to the suppression of ANLN and mTOR. Moreover, these studies illustrate that rational therapeutic targets for familial FSGS can be identified through biochemical characterization of dysregulated podocyte phenotypes.

scholarly journals IDH3α regulates one-carbon metabolism in glioblastoma

2019 ◽  
Vol 5 (1) ◽  
pp. eaat0456 ◽  
Author(s):  
Jasmine L. May ◽  
Fotini M. Kouri ◽  
Lisa A. Hurley ◽  
Juan Liu ◽  
Serena Tommasini-Ghelfi ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Carbon Metabolism ◽  
Tca Cycle ◽  
Metabolic Reprogramming ◽  
Metabolic Adaptation ◽  
Normal Brain ◽  
Loss Of Function ◽  
Mitochondrial Energy Metabolism ◽  
Signaling Axis ◽  
One Carbon Metabolism

Mutation or transcriptional up-regulation of isocitrate dehydrogenases 1 and 2 (IDH1andIDH2) promotes cancer progression through metabolic reprogramming and epigenetic deregulation of gene expression. Here, we demonstrate that IDH3α, a subunit of the IDH3 heterotetramer, is elevated in glioblastoma (GBM) patient samples compared to normal brain tissue and promotes GBM progression in orthotopic glioma mouse models. IDH3α loss of function reduces tricarboxylic acid (TCA) cycle turnover and inhibits oxidative phosphorylation. In addition to its impact on mitochondrial energy metabolism, IDH3α binds to cytosolic serine hydroxymethyltransferase (cSHMT). This interaction enhances nucleotide availability during DNA replication, while the absence of IDH3α promotes methionine cycle activity,S-adenosyl methionine generation, and DNA methylation. Thus, the regulation of one-carbon metabolism via an IDH3α-cSHMT signaling axis represents a novel mechanism of metabolic adaptation in GBM.

scholarly journals Cucurbitacin B Induces the Lysosomal Degradation of EGFR and Suppresses the CIP2A/PP2A/Akt Signaling Axis in Gefitinib-Resistant Non-Small Cell Lung Cancer

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 647 ◽  
Author(s):  
Pengfei Liu ◽  
Yuchen Xiang ◽  
Xuewen Liu ◽  
Te Zhang ◽  
Rui Yang ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Akt Signaling ◽  
Small Cell ◽  
Lysosomal Degradation ◽  
Small Cell Lung ◽  
Anticancer Effects ◽  
Signaling Axis ◽  
Phosphatase 2A ◽  
Nsclc Patients

Non-small cell lung cancer (NSCLC) patients carrying an epidermal growth factor receptor (EGFR) mutation are initially sensitive to EGFR-tyrosine kinase inhibitors (TKIs) treatment, but soon develop an acquired resistance. The treatment effect of EGFR-TKIs-resistant NSCLC patients still faces challenges. Cucurbitacin B (CuB), a triterpene hydrocarbon compound isolated from plants of various families and genera, elicits anticancer effects in a variety of cancer types. However, whether CuB is a viable treatment option for gefitinib-resistant (GR) NSCLC remains unclear. Here, we investigated the anticancer effects and underlying mechanisms of CuB. We report that CuB inhibited the growth and invasion of GR NSCLC cells and induced apoptosis. The inhibitory effect of CuB occurred through its promotion of the lysosomal degradation of EGFR and the downregulation of the cancerous inhibitor of protein phosphatase 2A/protein phosphatase 2A/Akt (CIP2A/PP2A/Akt) signaling axis. CuB and cisplatin synergistically inhibited tumor growth. A xenograft tumor model indicated that CuB inhibited tumor growth in vivo. Immunohistochemistry results further demonstrated that CuB decreased EGFR and CIP2A levels in vivo. These findings suggested that CuB could suppress the growth and invasion of GR NSCLC cells by inducing the lysosomal degradation of EGFR and by downregulating the CIP2A/PP2A/Akt signaling axis. Thus, CuB may be a new drug candidate for the treatment of GR NSCLC.

scholarly journals Human FBXL8 Is a Novel E3 Ligase Which Promotes BRCA Metastasis by Stimulating Pro-Tumorigenic Cytokines and Inhibiting Tumor Suppressors

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2210
Author(s):  
Shu-Chun Chang ◽  
Wayne Hsu ◽  
Emily Chia-Yu Su ◽  
Chin-Sheng Hung ◽  
Jeak Ling Ding
Keyword(s):  
Cancer Progression ◽  
Tumor Suppressors ◽  
Ex Vivo ◽  
E3 Ligase ◽  
Migration And Invasion ◽  
Loss Of Function ◽  
Protein Levels ◽  
Signaling Axis ◽  
Underlying Mechanisms ◽  
Gain Loss

The initiation and progression of breast cancer (BRCA) is associated with inflammation and immune-overactivation, which is critically modulated by the E3 ubiquitin ligase. However, the underlying mechanisms and key factors involved in BRCA formation and disease advancement remains under-explored. By retrospective studies of BRCA patient tissues; and gene knockdown and gain/loss-of-function studies, we uncovered a novel E3 ligase, FBXL8, in BRCA. A signature expression profile of F-box factors that specifically target and degrade proteins involved in cell death/survival, was identified. FBXL8 emerged as a prominent member of the F-box factors. Ex vivo analysis of 1349 matched BRCA tissues indicated that FBXL8 promotes cell survival and tumorigenesis, and its level escalates with BRCA progression. Knockdown of FBXL8 caused: (i) intrinsic apoptosis, (ii) inhibition of cell migration and invasion, (iii) accumulation of two tumor-suppressors, CCND2 and IRF5, and (iv) downregulation of cancer-promoting cytokines/chemokines; all of which curtailed the tumor microenvironment and displayed potential to suppress cancer progression. Co-IP study suggests that two tumor-suppressors, CCND2 and IRF5 are part of the immune-complex of FBXL8. The protein levels of CCND2 and IRF5 inversely correlated with FBXL8 expression, implying that FBXL8 E3 ligase was associated with the degradation of CCND2 and IRF5. Altogether, we propose the exploitation of the ubiquitin signaling axis of FBXL8-CCND2-IRF5 for anti-cancer strategies and potential therapeutics.

Role of Regulatory Oncogenic or Tumor Suppressor miRNAs of PI3K/AKT Signaling Axis in the Pathogenesis of Colorectal Cancer

2019 ◽  
Vol 24 (39) ◽  
pp. 4605-4610 ◽  
Author(s):  
Atena Soleimani ◽  
Farzad Rahmani ◽  
Gordon A. Ferns ◽  
Mikhail Ryzhikov ◽  
Amir Avan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Tumor Suppressor ◽  
Current Knowledge ◽  
Akt Signaling ◽  
Tumor Tissues ◽  
Radio Therapy ◽  
Signaling Axis ◽  
Cancer Tumor ◽  
Novel Biomarkers

Colorectal cancer (CRC) is the leading cause of cancer death worldwide and its incidence is increasing. In most patients with CRC, the PI3K/AKT signaling axis is over-activated. Regulatory oncogenic or tumor suppressor microRNAs (miRNAs) for PI3K/AKT signaling regulate cell proliferation, migration, invasion, angiogenesis, as well as resistance to chemo-/radio-therapy in colorectal cancer tumor tissues. Thus, regulatory miRNAs of PI3K/AKT/mTOR signaling represent novel biomarkers for new patient diagnosis and obtaining clinically invaluable information from post-treatment CRC patients for improving therapeutic strategies. This review summarizes the current knowledge of miRNAs’ regulatory roles of PI3K/AKT signaling in CRC pathogenesis.

scholarly journals LINC01089 functions as a ceRNA for miR-152-3p to inhibit non‐small lung cancer progression through regulating PTEN

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Huixian Zhang ◽  
Hao Zhang ◽  
Xingya Li ◽  
Siyuan Huang ◽  
Qianqian Guo ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Progression ◽  
Expression Level ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Loss Of Function ◽  
Protein Coding ◽  
Tensin Homolog ◽  
Pten Mrna

Abstract Background Long non-coding RNAs (lncRNAs) have been reported to exert crucial functions in regulating the progression of human cancers. However, the function and mechanism of long intergenic non-protein coding RNA 01089 (LINC01089) in non-small cell lung cancer (NSCLC) have not been revealed. Methods The expression level of LINC01089, microRNA (miRNA, miR)-152-3p and phosphatase and tensin homolog deleted onc hromosome ten (PTEN) mRNA was detected by quantitative real-time PCR (qRT-PCR). After gain-of-function and loss-of-function models were established with NSCLC cell lines, the proliferation, migration and invasion of NSCLC cells were detected by cell counting kit-8 (CCK-8) assay, scratch healing assay, Transwell assay, respectively. Dual luciferase reporter assay was employed to validate the binding relationship between miR-152-3p and LINC01089 or the 3’UTR of PTEN. Western blot was used to detect PTEN expression in NSCLC cells after LINC01089 and miR-152-3p were selectively modulated. Results LINC01089 was down-regulated in NSCLC tissues and cells. Functional experiments showed that knockdown of LINC01089 could promote the proliferation, migration and invasion of NSCLC cells, while over-expression of LINC01089 had the opposite effects. miR-152-3p was identified as a functional target for LIN01089, and miR-152-3p could reverse the function of LINC01089. Additionally, LINC01089 could up-regulate the expression level of PTEN via repressing miR-152-3p. Conclusions Down-regulation of LINC01089 promoted the progression of NSCLC through regulating miR-152-3p/PTEN axis.

scholarly journals Decreased level of miR-1301 promotes colorectal cancer progression via activation of STAT3 pathway

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Fangfang Yang ◽  
Hua Wang ◽  
Bianbian Yan ◽  
Tong Li ◽  
Lulu Min ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Migration ◽  
Cancer Progression ◽  
Luciferase Assay ◽  
Migration And Invasion ◽  
Loss Of Function ◽  
Aberrant Expression ◽  
Cell Migration And Invasion ◽  
Lovo Cells ◽  
Colorectal Cancer Progression

Abstract The molecular pathogenesis of colorectal cancer (CRC) has been widely investigated in recent years. Accumulating evidence has indicated that microRNA (miRNA) dysregulation participates in the processes of driving CRC initiation and progression. Aberrant expression of miR-1301 has been found in various tumor types. However, its role in CRC remains to be elucidated. In the present study, we identified miR-1301 was enriched in normal colorectal tissues and significantly down-regulated in CRC. Decreased level of miR-1301 strongly correlated with aggressive pathological characteristics, including advanced stage and metastasis. Bioinformatics and dual luciferase assay demonstrated that STAT3 is a direct target of miR-1301. Gain and loss-of-function assays showed that miR-1301 had no effect on cell proliferation. Overexpression of miR-1301 suppressed cell migration and invasion capacity of pSTA3-positive LoVo cells, but not pSTAT3-negative SW480 cells, while inhibition of miR-1301 consistently promoted cell migration and invasion in both cell lines. Additionally, miR-1301 inhibition restored the suppressed migration and invasion of STAT3- knockdown LoVo cells. MiR-1301 functioned as a tumor suppressor to modulate the IL6/STAT3 signaling pathway. In summary, this study highlights the significant role of miR- 1301/STAT3 axis in CRC metastasis.

scholarly journals Long noncoding RNA LINC00941 promotes pancreatic cancer progression by competitively binding miR-335-5p to regulate ROCK1-mediated LIMK1/Cofilin-1 signaling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jie Wang ◽  
Zhiwei He ◽  
Jian Xu ◽  
Peng Chen ◽  
Jianxin Jiang
Keyword(s):  
Pancreatic Cancer ◽  
Cell Growth ◽  
Cell Lines ◽  
Cancer Progression ◽  
Noncoding Rna ◽  
Epithelial Mesenchymal Transition ◽  
Loss Of Function ◽  
Mesenchymal Transition

AbstractAn accumulation of evidence indicates that long noncoding RNAs are involved in the tumorigenesis and progression of pancreatic cancer (PC). In this study, we investigated the functions and molecular mechanism of action of LINC00941 in PC. Quantitative PCR was used to examine the expression of LINC00941 and miR-335-5p in PC tissues and cell lines, and to investigate the correlation between LINC00941 expression and clinicopathological features. Plasmid vectors or lentiviruses were used to manipulate the expression of LINC00941, miR-335-5p, and ROCK1 in PC cell lines. Gain or loss-of-function assays and mechanistic assays were employed to verify the roles of LINC00941, miR-335-5p, and ROCK1 in PC cell growth and metastasis, both in vivo and in vitro. LINC00941 and ROCK1 were found to be highly expressed in PC, while miR-335-5p exhibited low expression. High LINC00941 expression was strongly associated with larger tumor size, lymph node metastasis, and poor prognosis. Functional experiments revealed that LINC00941 silencing significantly suppressed PC cell growth, metastasis and epithelial–mesenchymal transition. LINC00941 functioned as a molecular sponge for miR-335-5p, and a competitive endogenous RNA (ceRNA) for ROCK1, promoting ROCK1 upregulation, and LIMK1/Cofilin-1 pathway activation. Our observations lead us to conclude that LINC00941 functions as an oncogene in PC progression, behaving as a ceRNA for miR-335-5p binding. LINC00941 may therefore have potential utility as a diagnostic and treatment target in this disease.

scholarly journals Keap1 deletion accelerates mutant K-ras/p53-driven cholangiocarcinoma

2020 ◽  
Vol 318 (3) ◽  
pp. G419-G427 ◽  
Author(s):  
Tatsuhide Nabeshima ◽  
Shin Hamada ◽  
Keiko Taguchi ◽  
Yu Tanaka ◽  
Ryotaro Matsumoto ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cancer Progression ◽  
Stress Responses ◽  
Target Genes ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Related Factor ◽  
Loss Of Function ◽  
P53 Expression ◽  
Nrf2 Activation

The activation of the Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) pathway contributes to cancer progression in addition to oxidative stress responses. Loss-of-function Keap1 mutations were reported to activate Nrf2, leading to cancer progression. We examined the effects of Keap1 deletion in a cholangiocarcinoma mouse model using a mutant K-ras/ p53 mouse. Introduction of the Keap1 deletion into liver-specific mutant K-ras/ p53 expression resulted in the formation of invasive cholangiocarcinoma. Comprehensive analyses of the gene expression profiles identified broad upregulation of Nrf2-target genes such as Nqo1 and Gstm1 in the Keap1-deleted mutant K-ras/ p53 expressing livers, accompanied by upregulation of cholangiocyte-related genes. Among these genes, the transcriptional factor Sox9 was highly expressed in the dysplastic bile duct. The Keap-Nrf2-Sox9 axis might serve as a novel therapeutic target for cholangiocarcinoma. NEW & NOTEWORTHY The Keap1-Nrf2 system has a wide variety of effects in addition to the oxidative stress response in cancer cells. Addition of the liver-specific Keap1 deletion to mice harboring mutant K-ras and p53 accelerated cholangiocarcinoma formation, together with the hallmarks of Nrf2 activation. This process involved the expansion of Sox9-positive cells, indicating increased differentiation toward the cholangiocyte phenotype.

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