Inhibition of the DNA-Dependent Protein Kinase Catalytic Subunit Radiosensitizes Malignant Glioma Cells by Inducing Autophagy

Daido, Shigeru; Yamamoto, Akira; Fujiwara, Keishi; Sawaya, Raymond; Kondo, Seiji; Kondo, Yasuko

doi:10.1158/0008-5472.can-04-4202

Cited by 160 publications

(146 citation statements)

References 39 publications

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“…42 With regard to PRKDC, its connection to the autophagy pathway is less clear, albeit there is evidence suggesting the presence of such a link. 38,43,44 The mobilization of autophagy via these DDR transducers can be prosurvival 38,39,[45][46][47][48] or antisurvival; 38,39,48,49 and the dual roles that autophagy plays in cell fate determination under DNA damage stress conditions add to the complexity of its involvement in DDR, and may influence the outcome of anticancer chemotherapy. The interplay between DDR and autophagy is a burgeoning area of research in the autophagy field, linking autophagy with genomic integrity.…”

Section: Three Classes Of Ptdins3k and Pi3k Enzymesmentioning

confidence: 99%

Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy

2015

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Abbreviations: 3-MA, 3-methyladenine; AMBRA1, autophagy/Beclin 1 regulator 1; ATG, autophagy related; ATM, ATM serine/threonine kinase; ATR, ATR serine/threonine kinase; BH3, Bcl-2 homology 3; CCD, coiled-coil domain; CDK, cyclin-dependent kinase; CISD2, CDGSH iron sulfur domain 2; class I/II PI3K, class I/II phosphoinositide 3-kinase; class III PtdIns3K, class III phosphatidylinositol 3-kinase; DAPK1, death-associated protein kinase 1; DDR, DNA damage response; EIF4EBP1, eukaryotic translation initiation factor 4E binding protein 1; ER, endoplasmic reticulum; FOXO, forkhead box O; FYCO1, FYVE and coiledcoil domain containing 1; GAP, GTPase-activating protein; HMGB1, high mobility group box 1; HSPA1A, heat shock 70kDa protein 1A; IR, ionizing radiation; MAPK8, mitogen-activated protein kinase 8; MEFs, mouse embryonic fibroblasts; MTMR, myotubularin-related protein; MTOR, mechanistic target of rapamycin (serine/threonine kinase); MTORC1, mechanistic target of rapamycin complex 1; MVBs, spherical multivesicular bodies; NRBF2, nuclear receptor binding factor 2; PAS, phagophore assembly site; PDPK1, 3-phosphoinositide dependent protein kinase 1; PE, phosphatidylethanolamine; PIKFYVE, phosphoinositide kinase, FYVE finger containing; PINK1, PTEN-induced putative kinase 1; PtdIns3K-C1, class III phosphatidylinositol 3-kinase complex I; PtdIns3K-C2, class III phosphatidylinositol 3-kinase complex II; PKB, protein kinase B; PRKA, protein kinase, AMP-activated; PRKD1, protein kinase D1; PRKDC, protein kinase, DNA-activated, catalytic polypeptide; PtdIns5P, phosphatidylinositol 5-phosphate; PtdIns4P, phosphatidylinositol 4-phosphate; PtdIns(4,5)P 2 , phosphatidylinositol 4,5-bisphosphate; PtdIns3P, phosphatidylinositol 3-phosphate; PtdIns(3,5)P 2 , phosphatidylinositol 3,5-bisphosphate; PtdIns(3,4,5)P 3 , phosphatidylinositol 3,4,5-trisphosphate; RHEB, Ras homolog enriched in brain; RPS6KB1, ribosomal protein S6 kinase, 70kDa, polypeptide 1; SQSTM1, sequestosome 1; TECPR1, tectonin b-propeller repeat containing 1; TFEB, transcription factor EB; TRIM28, tripartite motif containing 28; TSC, tuberous sclerosis; UV, ultraviolet; UVRAG, UV radiation resistance associated; WDFY3, WD repeat and FYVE domain containing 3; WIPI, WD repeat domain, phosphoinositide interacting; ZFYVE1, zinc finger, FYVE domain containing 1.Autophagy is an evolutionarily conserved and exquisitely regulated self-eating cellular process with important biological functions. Phosphatidylinositol 3-kinases (PtdIns3Ks) and phosphoinositide 3-kinases (PI3Ks) are involved in the autophagic process. Here we aim to recapitulate how 3 classes of these lipid kinases differentially regulate autophagy. Generally, activation of the class I PI3K suppresses autophagy, via the well-established PI3K-AKT-MTOR (mechanistic target of rapamycin) complex 1 (MTORC1) pathway. In contrast, the class III PtdIns3K catalytic subunit PIK3C3/Vps34 forms a protein complex with BECN1 and PIK3R4 and produces phosphatidylinositol 3-phosphate (PtdIns3P), which is required for the initiati...

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Section: Three Classes Of Ptdins3k and Pi3k Enzymesmentioning

confidence: 99%

Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy

2015

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“…To detect and quantify acidic vesicular organelles, cells were stained with acridine orange as described previously (38). The number of acridine orange -positive cells was determined by fluorescence-activated cell sorting (FACS) analysis.…”

Section: Evaluation Of Acidic Vesicular Organellesmentioning

confidence: 99%

“…Plated cells were transfected with double-stranded siRNA targeting TG2 mRNA (Qiagen, Venlo, the Netherlands), PKCy (Santa Cruz Biotechnology, Santa Cruz, CA), and Beclin-1 (Santa Cruz Biotechnology) and control (nonsilencing) siRNA (Qiagen) and/or the GFP-LC3 fusion vector (22,38) using the Qiagen transfection reagent according to the manufacturer's protocol. Two siRNA sequences targeting TG2 were designed using siRNA-designing software (Qiagen).…”

Section: Transfections With Sirna and Gfp-lc3 Plasmidmentioning

confidence: 99%

Tissue Transglutaminase Inhibits Autophagy in Pancreatic Cancer Cells

Akar

Özpolat

Mehta

et al. 2007

Molecular Cancer Research

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Elevated expression of tissue transglutaminase (TG2) in cancer cells has been implicated in the development of drug resistance and metastatic phenotypes. However, the role and the mechanisms that regulate TG2 expression remain elusive. Here, we provide evidence that protein kinase CD (PKCD) regulates TG2 expression, which in turn inhibits autophagy, a type II programmed cell death, in pancreatic cancer cells that are frequently insensitive to standard chemotherapeutic agents. Rottlerin, a PKCD-specific inhibitor, and PKCD small interfering RNA (siRNA) down-regulated the expression of TG2 mRNA and protein and induced growth inhibition without inducing apoptosis in pancreatic cancer cells. Inhibition of PKCD by rottlerin or knockdown of TG2 protein by a TG2-specific siRNA resulted in a marked increase in autophagy shown by presence of autophagic vacuoles in the cytoplasm, formation of the acidic vesicular organelles, membrane association of microtubule-associated protein 1 light chain 3 (LC3) with autophagosomes, and a marked induction of LC3-II protein, important hallmarks of autophagy, and by electron microscopy. Furthermore, inhibition of TG2 by rottlerin or by the siRNA led to accumulation of green fluorescent protein (GFP)-LC3-II in autophagosomes in pancreatic cancer cells transfected with GFP-LC3 (GFP-ATG8) expression vector. Knockdown of Beclin-1, a specific autophagy-promoting protein and the product of Becn1 (ATG6), inhibited rottlerin-induced and TG2 siRNA -induced autophagy, indicating that Beclin-1 is required for this process. These results revealed that PKCD plays a critical role in the expression of TG2, which in turn regulates autophagy. In conclusion, these results suggest a novel mechanism of regulation of TG2 and TG2-mediated autophagy in pancreatic cancer cells.

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“…GFP-LC3 cells present a diffuse distribution under control conditions, whereas a punctate pattern of GFP-LC3 expression (GFP-LC3 dots) is induced by autophagy. In the current study, we determined the prevalence of autophagic cells (i.e., cells expressing GFP-LC3 dots) by using the GFP-LC3 expression vector kindly provided by Dr Noboru Mizushima (Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan), as described previously (Daido et al, 2005;Kanzawa et al, 2005). Tumor cells were transiently transfected with this vector by using Fugene 6 transfection reagent (Roche).…”

Section: Assessment Of the Involvement Of Lc3mentioning

confidence: 99%

Silencing mammalian target of rapamycin signaling by small interfering RNA enhances rapamycin-induced autophagy in malignant glioma cells

et al. 2006

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The mammalian target of rapamycin (mTOR) plays a central role in regulating the proliferation of malignant glioma cells, and mTOR-specific inhibitors such as rapamycin analogs are considered as promising therapy for malignant gliomas. However, the efficacy of mTOR inhibitors alone in the treatment of patients with malignant gliomas is only modest, potentially because these agents rather than acting as mTOR kinase inhibitors instead interfere with the function of only mTOR/raptor (regulatory-associated protein of mTOR) complex and thus do not perturb all mTOR functions. The purpose of this study was to determine whether global inhibition of the mTOR molecule enhances the antitumor effect of rapamycin on malignant glioma cells. We showed that rapamycin induced autophagy and that inhibition of autophagy by small interfering RNA (siRNA) directed against autophagyrelated gene Beclin 1 attenuated the cytotoxicity of rapamycin in rapamycin-sensitive tumor cells, indicating that the autophagy was a primary mediator of rapamycin's antitumor effect rather than a protective response. Exogenous expression of an mTOR mutant interfering with its kinase activity markedly enhanced the incidence of rapamycin-induced autophagy. Moreover, silencing of mTOR with siRNA augmented the inhibitory effect of rapamycin on tumor cell viability by stimulating autophagy. Importantly, not only rapamycin-sensitive malignant glioma cells with PTEN mutations but also rapamycin-resistant malignant glioma cells with wild-type PTEN were sensitized to rapamycin by mTOR siRNA. These results indicate that rapamycin-induced autophagy is one of the agent's antitumor effects and that silencing or inhibiting mTOR kinase activity could enhance the effectiveness of rapamycin.

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Inhibition of the DNA-Dependent Protein Kinase Catalytic Subunit Radiosensitizes Malignant Glioma Cells by Inducing Autophagy

Cited by 160 publications

References 39 publications

Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy

Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy

Tissue Transglutaminase Inhibits Autophagy in Pancreatic Cancer Cells

Silencing mammalian target of rapamycin signaling by small interfering RNA enhances rapamycin-induced autophagy in malignant glioma cells

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