Dataset Information

Oxygen Tension Regulates Lysosomal Activation and Receptor Tyrosine Kinase Degradation.

ABSTRACT: Oxygen sensing is crucial for adaptation to variable habitats and physiological conditions. Low oxygen tension, or hypoxia, is a common feature of solid tumors, and hypoxic tumors are often more aggressive and resistant to therapy. Here we show that, in cultured mammalian cells, hypoxia suppressed lysosomal acidification/activation and receptor tyrosine kinase (RTK) degradation. Hypoxia down-regulated mTORc1, reducing its ability to activate transcription factor EB (TFEB), a master regulator of V-ATPase, the lysosomal proton pump. Hypoxia prevented epidermal growth factor receptor (EGFR) degradation in tumor tissues, whereas activation of lysosomes enhanced tumor cell response to anti-EGFR treatment. Our results link oxygen tension and lysosomal activity, provide a molecular explanation of the malignant phenotype associated with hypoxic tumors, and suggest activation of lysosomes may provide therapeutic benefit in RTK-targeted cancer therapy.

SUBMITTER: Hong J

PROVIDER: S-EPMC6896048 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Oxygen Tension Regulates Lysosomal Activation and Receptor Tyrosine Kinase Degradation.

Hong Jaewoo J Wuest Todd R TR Min Yongfen Y Lin P Charles PC

Cancers 20191025 11

Oxygen sensing is crucial for adaptation to variable habitats and physiological conditions. Low oxygen tension, or hypoxia, is a common feature of solid tumors, and hypoxic tumors are often more aggressive and resistant to therapy. Here we show that, in cultured mammalian cells, hypoxia suppressed lysosomal acidification/activation and receptor tyrosine kinase (RTK) degradation. Hypoxia down-regulated mTORc1, reducing its ability to activate transcription factor EB (TFEB), a master regulator of ...[more]

PMID: 31717697

Similar Datasets

Project description:Macroautophagy/autophagy is a central component of the cytoprotective cellular stress response. To enlighten stress-induced autophagy signaling, we screened a human kinome siRNA library for regulators of autophagic flux in MCF7 human breast carcinoma cells and identified the catalytic subunit of DNA-dependent protein kinase PRKDC/DNA-PKcs as a positive regulator of basal and DNA damage-induced autophagy. Analysis of autophagy-regulating signaling cascades placed PRKDC upstream of the AMP-dependent protein kinase (AMPK) complex and ULK1 kinase. In normal culture conditions, PRKDC interacted with the AMPK complex and phosphorylated its nucleotide-sensing γ1 subunit PRKAG1/AMPKγ1 at Ser192 and Thr284, both events being significantly reduced upon the activation of the AMPK complex. Alanine substitutions of PRKDC phosphorylation sites in PRKAG1 reduced AMPK complex activation without affecting its nucleotide sensing capacity. Instead, the disturbance of PRKDC-mediated phosphorylation of PRKAG1 inhibited the lysosomal localization of the AMPK complex and its starvation-induced association with STK11 (serine/threonine kinase 11). Taken together, our data suggest that PRKDC-mediated phosphorylation of PRKAG1 primes AMPK complex to the lysosomal activation by STK11 in cancer cells thereby linking DNA damage response to autophagy and cellular metabolism. Abbreviations: AXIN1: axin 1; 3-MA: 3-methyladenine; 5-FU: 5-fluorouracil; AA mutant: double alanine mutant (S192A, T284A) of PRKAG1; ACACA: acetyl-CoA carboxylase alpha; AICAR: 5-Aminoimidazole-4-carboxamide ribonucleotide; AMPK: AMP-activated protein kinase; ATG: autophagy-related; ATM: ataxia telangiectasia mutated; ATR: ATM serine/threonine kinase; AV: autophagic vacuole; AVd: degradative autophagic vacuole; AVi: initial autophagic vacuole; BECN1: beclin 1; BSA: bovine serum albumin; CBS: cystathionine beta-synthase; CDK7: cyclin dependent kinase 7; CDKN1A: cyclin dependent kinase inhibitor 1A; EGFP: enhanced green fluorescent protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GST: glutathione S transferase; H2AX/H2AFX: H2A.X variant histone; HBSS: Hanks balanced salt solution; IP: immunopurification; IR: ionizing radiation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAP3K9: mitogen-activated protein kinase kinase kinase 9; mRFP: monomeric red fluorescent protein; mCh: mCherry; MCM7: minichromosome maintenance complex component 7; MTORC1: mechanistic target of rapamycin kinase complex 1; NHEJ: non-homologous end joining; NRBP2: nuclear receptor binding protein 2; NTC: non-targeting control; NUAK1: NUAK family kinase 1; PBS: phosphate-buffered saline; PIK3AP1: phosphoinositide-3-kinase adaptor protein 1; PIK3CA: phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit alpha; PIKK: phosphatidylinositol 3-kinase-related kinase; PRKAA: protein kinase AMP-activated catalytic subunit alpha; PRKAB: protein kinase AMP-activated non-catalytic subunit beta; PRKAG: protein kinase AMP-activated non-catalytic subunit gamma; PRKDC: protein kinase, DNA-activated, catalytic subunit; RLuc: Renilla luciferase; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TP53: tumor protein p53; TSKS: testis specific serine kinase substrate; ULK1: unc-51 like autophagy activating kinase 1; WIPI2: WD repeat domain, phosphoinositide interacting 2; WT: wild type.

Project description:NF?B signaling is of paramount importance in the regulation of apoptosis, proliferation, and inflammatory responses during human development and homeostasis, as well as in many human cancers. Receptor Tyrosine Kinases (RTKs), including the Fibroblast Growth Factor Receptors (FGFRs) are also important in development and disease. However, a direct relationship between growth factor signaling pathways and NF?B activation has not been previously described, although FGFs have been known to antagonize TNF?-induced apoptosis.Here, we demonstrate an interaction between FGFR4 and IKK? (Inhibitor of NF?B Kinase ? subunit), an essential component in the NF?B pathway. This novel interaction was identified utilizing a yeast two-hybrid screen [1] and confirmed by coimmunoprecipitation and mass spectrometry analysis. We demonstrate tyrosine phosphorylation of IKK? in the presence of activated FGFR4, but not kinase-dead FGFR4. Following stimulation by TNF? (Tumor Necrosis Factor ?) to activate NF?B pathways, FGFR4 activation results in significant inhibition of NF?B signaling as measured by decreased nuclear NF?B localization, by reduced NF?B transcriptional activation in electophoretic mobility shift assays, and by inhibition of IKK? kinase activity towards the substrate GST-I?B? in in vitro assays. FGF19 stimulation of endogenous FGFR4 in TNF?-treated DU145 prostate cancer cells also leads to a decrease in IKK? activity, concomitant reduction in NF?B nuclear localization, and reduced apoptosis. Microarray analysis demonstrates that FGF19 + TNF? treatment of DU145 cells, in comparison with TNF? alone, favors proliferative genes while downregulating genes involved in apoptotic responses and NF?B signaling.These results identify a compelling link between FGFR4 signaling and the NF?B pathway, and reveal that FGFR4 activation leads to a negative effect on NF?B signaling including an inhibitory effect on proapoptotic signaling. We anticipate that this interaction between an RTK and a component of NF?B signaling will not be limited to FGFR4 alone.

Dataset Information

Oxygen Tension Regulates Lysosomal Activation and Receptor Tyrosine Kinase Degradation.

Publications

Oxygen Tension Regulates Lysosomal Activation and Receptor Tyrosine Kinase Degradation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets