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Di Blasio L, Gagliardi PA, Puliafito A, Primo L. Serine/Threonine Kinase 3-Phosphoinositide-Dependent Protein Kinase-1 (PDK1) as a Key Regulator of Cell Migration and Cancer Dissemination. Cancers (Basel) 2017; 9:cancers9030025. [PMID: 28287465 PMCID: PMC5366820 DOI: 10.3390/cancers9030025] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 02/03/2023] Open
Abstract
Dissecting the cellular signaling that governs the motility of eukaryotic cells is one of the fundamental tasks of modern cell biology, not only because of the large number of physiological processes in which cell migration is crucial, but even more so because of the pathological ones, in particular tumor invasion and metastasis. Cell migration requires the coordination of at least four major processes: polarization of intracellular signaling, regulation of the actin cytoskeleton and membrane extension, focal adhesion and integrin signaling and contractile forces generation and rear retraction. Among the molecular components involved in the regulation of locomotion, the phosphatidylinositol-3-kinase (PI3K) pathway has been shown to exert fundamental role. A pivotal node of such pathway is represented by the serine/threonine kinase 3-phosphoinositide-dependent protein kinase-1 (PDPK1 or PDK1). PDK1, and the majority of its substrates, belong to the AGC family of kinases (related to cAMP-dependent protein kinase 1, cyclic Guanosine monophosphate-dependent protein kinase and protein kinase C), and control a plethora of cellular processes, downstream either to PI3K or to other pathways, such as RAS GTPase-MAPK (mitogen-activated protein kinase). Interestingly, PDK1 has been demonstrated to be crucial for the regulation of each step of cell migration, by activating several proteins such as protein kinase B/Akt (PKB/Akt), myotonic dystrophy-related CDC42-binding kinases alpha (MRCKα), Rho associated coiled-coil containing protein kinase 1 (ROCK1), phospholipase C gamma 1 (PLCγ1) and β3 integrin. Moreover, PDK1 regulates cancer cell invasion as well, thus representing a possible target to prevent cancer metastasis in human patients. The aim of this review is to summarize the various mechanisms by which PDK1 controls the cell migration process, from cell polarization to actin cytoskeleton and focal adhesion regulation, and finally, to discuss the evidence supporting a role for PDK1 in cancer cell invasion and dissemination.
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Affiliation(s)
- Laura Di Blasio
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
| | | | | | - Luca Primo
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
- Department of Oncology, University of Torino, 10043 Orbassano, Torino, Italy.
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Regulation of PI3K effector signalling in cancer by the phosphoinositide phosphatases. Biosci Rep 2017; 37:BSR20160432. [PMID: 28082369 PMCID: PMC5301276 DOI: 10.1042/bsr20160432] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 12/24/2022] Open
Abstract
Class I phosphoinositide 3-kinase (PI3K) generates phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) at the plasma membrane in response to growth factors, activating a signalling cascade that regulates many cellular functions including cell growth, proliferation, survival, migration and metabolism. The PI3K pathway is commonly dysregulated in human cancer, and drives tumorigenesis by promoting aberrant cell growth and transformation. PtdIns(3,4,5)P3 facilitates the activation of many pleckstrin homology (PH) domain-containing proteins including the serine/threonine kinase AKT. There are three AKT isoforms that are frequently hyperactivated in cancer through mutation, amplification or dysregulation of upstream regulatory proteins. AKT isoforms have converging and opposing functions in tumorigenesis. PtdIns(3,4,5)P3 signalling is degraded and terminated by phosphoinositide phosphatases such as phosphatase and tensin homologue (PTEN), proline-rich inositol polyphosphate 5-phosphatase (PIPP) (INPP5J) and inositol polyphosphate 4-phosphatase type II (INPP4B). PtdIns(3,4,5)P3 is rapidly hydrolysed by PIPP to generate phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2), which is further hydrolysed by INPP4B to form phosphatidylinositol 3-phosphate (PtdIns3P). PtdIns(3,4)P2 and PtdIns3P are also important signalling molecules; PtdIns(3,4)P2 together with PtdIns(3,4,5)P3 are required for maximal AKT activation and PtdIns3P activates PI3K-dependent serum and glucocorticoid-regulated kinase (SGK3) signalling. Loss of Pten, Pipp or Inpp4b expression or function promotes tumour growth in murine cancer models through enhanced AKT isoform-specific signalling. INPP4B inhibits PtdIns(3,4)P2-mediated AKT activation in breast and prostate cancer; however, INPP4B expression is increased in acute myeloid leukaemia (AML), melanoma and colon cancer where it paradoxically promotes cell proliferation, transformation and/or drug resistance. This review will discuss how PTEN, PIPP and INPP4B distinctly regulate PtdIns(3,4,5)P3 signalling downstream of PI3K and how dysregulation of these phosphatases affects cancer outcomes.
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Gao Y, Yuan CY, Yuan W. Will targeting PI3K/Akt/mTOR signaling work in hematopoietic malignancies? Stem Cell Investig 2016; 3:31. [PMID: 27583254 DOI: 10.21037/sci.2016.07.02] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/06/2016] [Indexed: 12/12/2022]
Abstract
The constitutive activation of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway has been demonstrated to be critical in clinical cancer patients as well as in laboratory cancer models including hematological malignancies. Great efforts have been made to develop inhibitors targeting this pathway in hematological malignancies but so far the efficacies of these inhibitors were not as good as expected. By analyzing existing literatures and datasets available, we found that mutations of genes in the pathway only constitute a very small subset of hematological malignancies. Deep understanding of the function of gene, the pathway and/or its regulators, and the cellular response to inhibitors, may help us design better drugs targeting the hematological malignancies.
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Affiliation(s)
- Yanan Gao
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Chase Y Yuan
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China;; College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Weiping Yuan
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
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A Small Molecule Inhibitor of PDK1/PLCγ1 Interaction Blocks Breast and Melanoma Cancer Cell Invasion. Sci Rep 2016; 6:26142. [PMID: 27199173 PMCID: PMC4873738 DOI: 10.1038/srep26142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/21/2016] [Indexed: 12/02/2022] Open
Abstract
Strong evidence suggests that phospholipase Cγ1 (PLCγ1) is a suitable target to counteract tumourigenesis and metastasis dissemination. We recently identified a novel signalling pathway required for PLCγ1 activation which involves formation of a protein complex with 3-phosphoinositide-dependent protein kinase 1 (PDK1). In an effort to define novel strategies to inhibit PLCγ1-dependent signals we tested here whether a newly identified and highly specific PDK1 inhibitor, 2-O-benzyl-myo-inositol 1,3,4,5,6-pentakisphosphate (2-O-Bn-InsP5), could affect PDK1/PLCγ1 interaction and impair PLCγ1-dependent cellular functions in cancer cells. Here, we demonstrate that 2-O-Bn-InsP5 interacts specifically with the pleckstrin homology domain of PDK1 and impairs formation of a PDK1/PLCγ1 complex. 2-O-Bn-InsP5 is able to inhibit the epidermal growth factor-induced PLCγ1 phosphorylation and activity, ultimately resulting in impaired cancer cell migration and invasion. Importantly, we report that 2-O-Bn-InsP5 inhibits cancer cell dissemination in zebrafish xenotransplants. This work demonstrates that the PDK1/PLCγ1 complex is a potential therapeutic target to prevent metastasis and it identifies 2-O-Bn-InsP5 as a leading compound for development of anti-metastatic drugs.
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Du L, Chen X, Cao Y, Lu L, Zhang F, Bornstein S, Li Y, Owens P, Malkoski S, Said S, Jin F, Kulesz-Martin M, Gross N, Wang XJ, Lu SL. Overexpression of PIK3CA in murine head and neck epithelium drives tumor invasion and metastasis through PDK1 and enhanced TGFβ signaling. Oncogene 2016; 35:4641-52. [PMID: 26876212 PMCID: PMC4985507 DOI: 10.1038/onc.2016.1] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 12/12/2022]
Abstract
Head and neck squamous cell carcinoma (HNSCC) patients have a poor prognosis, with invasion and metastasis as major causes of mortality. The phosphatidylinositol 3-kinase (PI3K) pathway regulates a wide range of cellular processes crucial for tumorigenesis, and PIK3CA amplification and mutation are among the most common genetic alterations in human HNSCC. Compared to the well-documented roles of the PI3K pathway in cell growth and survival, the roles of the PI3K pathway in tumor invasion and metastasis have not been well delineated. We generated a PIK3CA-genetically engineered mouse model (PIK3CA-GEMM) in which wildtype PIK3CA is overexpressed in head and neck epithelium. Although PIK3CA overexpression alone was not sufficient to initiate HNSCC formation, it significantly increased tumor susceptibility in an oral-carcinogenesis mouse model. PIK3CA overexpression in mouse oral epithelium increased tumor invasiveness and metastasis by increasing epithelial-mesenchymal transition and by enriching a cancer stem cell phenotype in tumor epithelial cells. In addition to these epithelial alterations, we also observed marked inflammation in tumor stroma. AKT is a central signaling mediator of the PI3K pathway. However, molecular analysis suggested that progression of PIK3CA-driven HNSCC is facilitated by PDK1 and enhanced TGFβ signaling rather than by AKT. Examination of human HNSCC clinical samples revealed that both PIK3CA and PDK1 protein levels correlated with tumor progression, highlighting the significance of this pathway. In summary, our results offer significant insight into how PIK3CA-overexpression drives HNSCC invasion and metastasis, providing a rationale for targeting PI3K/PDK1 and TGFβ signaling in advanced HNSCC patients with PIK3CA amplification.
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Affiliation(s)
- L Du
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Otolaryngology, Fourth University Hospital of China Medical University, Shengyang, China
| | - X Chen
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Y Cao
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Surgical Oncology, The First University Hospital of China Medical University, Shengyang, Liaoning, China
| | - L Lu
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - F Zhang
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - S Bornstein
- Department of Otolaryngology, Oregon Health and Science University, Portland, OR, USA
| | - Y Li
- Department of Otolaryngology, Oregon Health and Science University, Portland, OR, USA
| | - P Owens
- Department of Otolaryngology, Oregon Health and Science University, Portland, OR, USA
| | - S Malkoski
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - S Said
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - F Jin
- Department of Surgical Oncology, The First University Hospital of China Medical University, Shengyang, Liaoning, China
| | - M Kulesz-Martin
- Department of Dermatology, Oregon Health and Science University, Portland, OR, USA
| | - N Gross
- Department of Otolaryngology, Oregon Health and Science University, Portland, OR, USA
| | - X-J Wang
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - S-L Lu
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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HER Specific TKIs Exert Their Antineoplastic Effects on Breast Cancer Cell Lines through the Involvement of STAT5 and JNK. PLoS One 2016; 11:e0146311. [PMID: 26735495 PMCID: PMC4703392 DOI: 10.1371/journal.pone.0146311] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/15/2015] [Indexed: 12/14/2022] Open
Abstract
Background HER-targeted tyrosine kinase inhibitors (TKIs) have demonstrated pro-apoptotic and antiproliferative effects in vitro and in vivo. The exact pathways through which TKIs exert their antineoplastic effects are, however, still not completely understood. Methods Using Milliplex assays, we have investigated the effects of the three panHER-TKIs lapatinib, canertinib and afatinib on signal transduction cascade activation in SKBR3, T47D and Jurkat neoplastic cell lines. The growth-inhibitory effect of blockade of HER and of JNK and STAT5 signaling was measured by proliferation- and apoptosis-assays using formazan dye labeling of viable cells, Western blotting for cleaved PARP-1 and immunolabeling for active caspase 3, respectively. Results All three HER-TKIs clearly inhibited proliferation and increased apoptosis in HER2 overexpressing SKBR3 cells, while their effect was less pronounced on HER2 moderately expressing T47D cells where they exerted only a weak antiproliferative and essentially no pro-apoptotic effect. Remarkably, phosphorylation/activation of JNK and STAT5A/B were inhibited by HER-TKIs only in the sensitive, but not in the resistant cells. In contrast, phosphorylation/activation of ERK/MAPK, STAT3, CREB, p70 S6 kinase, IkBa, and p38 were equally affected by HER-TKIs in both cell lines. Moreover, we demonstrated that direct pharmacological blockade of JNK and STAT5 abrogates cell growth in both HER-TKI-sensitive as well as -resistant breast cancer cells, respectively. Conclusion We have shown that HER-TKIs exert a HER2 expression-dependent anti-cancer effect in breast cancer cell lines. This involves blockade of JNK and STAT5A/B signaling, which have been found to be required for in vitro growth of these cell lines.
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Fan Y, Wang Y, Wang K. Prostaglandin E2 stimulates normal bronchial epithelial cell growth through induction of c-Jun and PDK1, a kinase implicated in oncogenesis. Respir Res 2015; 16:149. [PMID: 26684827 PMCID: PMC4699375 DOI: 10.1186/s12931-015-0309-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 12/04/2015] [Indexed: 02/05/2023] Open
Abstract
Background Cyclooxygenase-2-derived prostaglandin E2 (PGE2), a bioactive eicosanoid, has been implicated in many biological processes including reproduction, inflammation and tumor growth. We previously showed that PGE2 stimulated lung cancer cell growth and progression through PGE2 receptor EP2/EP4-mediated kinase signaling pathways. However, the role of PGE2 in controlling lung airway epithelial cell phenotype remains unknown. We evaluated the effects of c-Jun and 3-phosphoinositede dependent protein kinase-1 (PDK1) in mediating epithelial cell hyperplasia induced by PGE2. Method The bronchial epithelial cell lines BEAS-2B and HBEc14-KT were cultured and then treated with PGE2. PDK1 small interfering RNA (siRNA) and a PDK1 inhibitor, an antagonist of the PGE2 receptor subtype EP4 and EP4 siRNA, c-Jun siRNA, and overexpressions of c-Jun and PDK1 have been used to evaluate the effects on cell proliferation. Results We demonstrated that PGE2 increased normal bronchial epithelial cell proliferation through induction of PDK1, an ankyrin repeat-containing Ser/Thr kinase implicated in the induction of apoptosis and the suppression of tumor growth. PDK1 siRNA and a PDK1 inhibitor blocked the effects of PGE2 on normal cell growth. The PGE2-induced PDK1 expression was blocked by an antagonist of the PGE2 receptor subtype EP4 and by EP4 siRNA. In addition, we showed that induction of PDK1 by PGE2 was associated with induction of the transcription factor, c-Jun protein. Silencing of c-Jun using siRNA and point mutations of c-Jun sites in the PDK1 gene promoter resulted in blockade of PDK1 expression and promoter activity induced by PGE2. In contrast, overexpression of c-Jun induced PDK1 gene promoter activity and expression followed increased cell proliferation. Conclusion PGE2 increases normal bronchial epithelial cell proliferation through increased PDK1 gene expression that is dependent on EP4 and induction of c-Jun. Therewith, our data suggest a new role of c-Jun and PDK1 in mediating epithelial cell hyperplasia induced by PGE2.
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Affiliation(s)
- Yu Fan
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China. .,Department of Radiotherapy, Sichuan Cancer Hospital, Chengdu, Sichuan Province, 610041, China.
| | - Ye Wang
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China.
| | - Ke Wang
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China.
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PDK1: A signaling hub for cell migration and tumor invasion. Biochim Biophys Acta Rev Cancer 2015; 1856:178-88. [DOI: 10.1016/j.bbcan.2015.07.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 07/28/2015] [Indexed: 01/22/2023]
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Effects of 5-Amyno-4-(1,3-benzothyazol-2-yn)-1-(3-methoxyphenyl)-1,2-dihydro-3H-pyrrol-3-one Intake on Digestive System in a Rat Model of Colon Cancer. ScientificWorldJournal 2015; 2015:376576. [PMID: 26504896 PMCID: PMC4609483 DOI: 10.1155/2015/376576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 09/02/2015] [Accepted: 09/09/2015] [Indexed: 12/30/2022] Open
Abstract
Introduction. Pyrrol derivate 5-amyno-4-(1,3-benzothyazol-2-yn)-1-(3-methoxyphenyl)-1,2-dihydro-3H-pyrrol-3-one (D1) has shown antiproliferative activities in vitro, so investigation of the impact of D1 intake on gut organs in rats that experienced colon cancer seems to be necessary. Materials and Methods. D1 at the dose of 2.3 mg/kg was administered per os daily for 27 (from the 1st day of experiment) or 7 (from the 21st week of experiment) weeks to rats that experienced 1,2-dimethylhydrazine (DMH)-induced colon cancer for 20 weeks. 5-Fluorouracil (5FU) was chosen as reference drug and was administered intraperitoneally weekly for 7 weeks (from the 21st week of experiment) at the dose of 45 mg/kg. Results. Antitumor activity of D1 comparable with the 5FU one against DMH-induced colon cancer in rats was observed (decrease of tumor number and tumor total area up to 46%). D1 attenuated the inflammation of colon, gastric and jejunal mucosa, and the liver, caused by DMH, unlike 5FU, aggravating the latter. In addition, D1 partially normalized mucosa morphometric parameters suggesting its functional restore. Conclusions. D1 possesses, comparable with 5-fluorouracil antitumor efficacy, less damaging effects on the tissues beyond cancerous areas and contributes to partial morphological and functional gut organs recovery.
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PDK1 promotes tumor growth and metastasis in a spontaneous breast cancer model. Oncogene 2015; 35:3314-23. [DOI: 10.1038/onc.2015.393] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 09/06/2015] [Accepted: 09/08/2015] [Indexed: 12/25/2022]
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Bai X, Li P, Xie Y, Guo C, Sun Y, Xu Q, Zhao D. Overexpression of 3-phosphoinositide-dependent protein kinase-1 is associated with prognosis of gastric carcinoma. Tumour Biol 2015; 37:2333-9. [DOI: 10.1007/s13277-015-4024-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 08/31/2015] [Indexed: 01/03/2023] Open
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Downregulated AEG-1 together with inhibited PI3K/Akt pathway is associated with reduced viability of motor neurons in an ALS model. Mol Cell Neurosci 2015; 68:303-13. [PMID: 26320681 DOI: 10.1016/j.mcn.2015.08.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 06/16/2015] [Accepted: 08/18/2015] [Indexed: 11/24/2022] Open
Abstract
Astrocyte elevated gene-1 (AEG-1) has been reported to regulate the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and is also regulated by it. This study investigated how AEG-1 participates in the survival pathway of motor neurons in amyotrophic lateral sclerosis (ALS). We found reduced levels of AEG-1 in ALS motor neurons, both in vivo and in vitro, compared to wild type controls. Moreover, AEG-1 silencing demonstrated inhibition of the PI3K/Akt pathway and increased cell apoptosis. Additionally, the PI3K/Akt pathway in mSOD1 cells was unresponsive under serum deprivation conditions compared to wtSOD1 cells. These results suggest that AEG-1 deficiency, together with the inhibited PI3K/Akt pathway was associated with decreased viability of ALS motor neurons. However, the mRNA levels of AEG-1 were still lower in mSOD1 cells compared to the control groups, though the signaling pathway was activated by application of a PI3-K activator. This suggests that in ALS motor neurons, some unknown interruption exists in the PI3K/Akt/CREB/AEG-1 feedback loop, thus attenuating the protection by this signaling pathway. Together, these findings support that AEG-1 is a critical factor for cell survival, and the disrupted PI3K/Akt/CREB/AEG-1cycle is involved in the death of injured motor neurons and pathogenesis of ALS.
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Chiang KC, Chen HY, Hsu SY, Pang JHS, Wang SY, Hsu JT, Yeh TS, Chen LW, Kuo SF, Sun CC, Lee JM, Yeh CN, Juang HH. PTEN insufficiency modulates ER+ breast cancer cell cycle progression and increases cell growth in vitro and in vivo. Drug Des Devel Ther 2015; 9:4631-8. [PMID: 26316702 PMCID: PMC4541544 DOI: 10.2147/dddt.s86184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Phosphatase and tensin homolog (PTEN), a well-known tumor suppressor gene and frequently mutated or lost in breast cancer, possesses the negative regulation function over the PI3K/Akt/mTOR pathway. PTEN insufficiency has been associated with advanced breast cancer and poor prognosis of breast cancer patients. Recently, target therapies aimed at PI3K/Akt/mTOR pathway to treat breast cancer have got popularity. However, the exact effect of PTEN on breast cancer cells is still not well understood. This study demonstrated that PTEN knockdown in MCF-7 cells strengthened the downstream gene expressions, including p-Akt, p-ERK1/2, p-mTOR, p-p70s6k, and p-GSK3β. PTEN knockdown MCF-7 cells had increased cell growth and Ki-67 expression. Further Western blot demonstrated that p27 was repressed obviously with p21 slightly inhibited and CDK1, 2, 4, 6, cyclin A, and Cdc25C were upregulated in MCF-7 PTEN knockdown cells, leading to the higher growth rate. More importantly, PTEN knockdown MCF-7 cells had higher tumorigenesis and tumor growth in vivo. From our current work, we provided more detailed PTEN-mediated mechanisms to stimulate ER+ breast cancer cell growth. Our result may pave the way for further target therapy development used alone or in combination with other drugs for ER+ breast cancer with PTEN insufficiency.
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Affiliation(s)
- Kun-Chun Chiang
- Department of General Surgery, Chang Gung Memorial Hospital, Chang Gung University, Keelung, Republic of China
- Department of General Surgery, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Huang-Yang Chen
- Department of General Surgery, Chang Gung Memorial Hospital, Chang Gung University, Keelung, Republic of China
| | - Shu-Yuan Hsu
- Department of Anatomy, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Jong-Hwei S Pang
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Shang-Yu Wang
- Department of General Surgery, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Jun-Te Hsu
- Department of General Surgery, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Ta-Sen Yeh
- Department of General Surgery, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Li-Wei Chen
- Department of Gastroenterology, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Sheng-Fong Kuo
- Department of Endocrinology and Metabolism, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Chi-Chin Sun
- Department of Ophthalmology, Chang Gung Memorial Hospital, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Jim-Ming Lee
- Department of General Surgery, Chang Gung Memorial Hospital, Chang Gung University, Keelung, Republic of China
| | - Chun-Nan Yeh
- Department of General Surgery, Chang Gung University, Keelung, Taiwan, Republic of China
| | - Horng-Heng Juang
- Department of Anatomy, Chang Gung University, Keelung, Taiwan, Republic of China
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Abstract
Background With one million new cases of colorectal cancer (CRC) diagnosed annually in the world, CRC is the third most commonly diagnosed cancer in the Western world. Patients with stage I-III CRC can be cured with surgery but are at risk for recurrence. Colorectal cancer is characterized by the presence of chromosomal deletions and gains. Large genomic profiling studies have however not been conducted in this disease. The number of a specific genetic aberration in a tumour sample could correlate with recurrence-free survival or overall survival, possibly leading to its use as biomarker for therapeutic decisions. At this point there are not sufficient markers for prediction of disease recurrence in colorectal cancer, which can be used in the clinic to discriminate between stage II patients who will benefit from adjuvant chemotherapy. For instance, the benefit of adjuvant chemotherapy has been most clearly demonstrated in stage III disease with an approximately 30 percent relative reduction in the risk of disease recurrence. The benefits of adjuvant chemotherapy in stage II disease are less certain, the risk for relapse is much smaller in the overall group and the specific patients at risk are hard to identify. Materials and Methods In this study, array-comparative genomic hybridization analysis (array-CGH) was applied to study high-resolution DNA copy number alterations in 93 colon carcinoma samples. These genomic data were combined with parameters like KRAS mutation status, microsatellite status and clinicopathological characteristics. Results Both large and small chromosomal losses and gains were identified in our sample cohort. Recurrent gains were found for chromosome 1q, 7, 8q, 13 and 20 and losses were mostly found for 1p, 4, 8p, 14, 15, 17p, 18, 21 and 22. Data analysis demonstrated that loss of chromosome 4 is linked to a worse prognosis in our patients series. Besides these alterations, two interesting small regions of overlap were identified, which could be associated with disease recurrence. Gain of the 16p13.3 locus (including the RNA binding protein, fox-1 homolog gene, RBFOX1) was linked with a worse recurrence-free survival in our patient cohort. On the other hand, loss of RBFOX1 was only found in patients without disease recurrence. Most interestingly, above mentioned characteristics were also found in stage II patients, for whom there is a high medical need for the identification of new prognostic biomarkers. Conclusions In conclusion, copy number variation of the 16p13.3 locus seems to be an important parameter for prediction of disease recurrence in colon cancer.
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Xu Z, Liao B, Zhang R, Yao J, Shi R, Wang L. Expression of 3-phosphoinositide-dependent protein kinase 1 in colorectal cancer as a potential therapeutic target. Med Oncol 2015; 32:198. [PMID: 26055151 DOI: 10.1007/s12032-015-0645-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 05/21/2015] [Indexed: 01/05/2023]
Abstract
3-Phosphoinositide-dependent protein kinase 1 (PDK1) is centrally involved in cancer progression, including proliferation, apoptosis and invasion. However, its expression pattern and possible cellular functions in human colorectal cancer remain unclear. In the present study, we show that PDK1 expression is up-regulated at both mRNA and protein levels in colorectal cancer clinical specimens and cell lines. Transient knockdown of PDK1 suppresses cellular growth, induces cellular apoptosis and causes abnormal cell cycle distribution. Meanwhile, decreased PDK1 level is closely associated with reduced Akt/cyclin D1 activity. Activating AKT activity and reintroducing cyclin D1 expression significantly compromised the oncogenic activity induced by PDK1. Together, our findings elucidate a key role for PDK1 in colorectal cellular functions trigged by the Akt/cyclin D1 pathway, thus providing a novel insight of PDK1 in colorectal carcinogenesis.
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Affiliation(s)
- Zhenglei Xu
- Department of Gastroenterology, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, 1017#, North Dongmen Road, Shenzhen, 518000, Guangdong Province, People's Republic of China
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Bermúdez M, Imaz-Rosshandler I, Rangel-Escareño C, Zeichner-David M, Arzate H, Mercado-Celis GE. CEMP1 Induces Transformation in Human Gingival Fibroblasts. PLoS One 2015; 10:e0127286. [PMID: 26011628 PMCID: PMC4444236 DOI: 10.1371/journal.pone.0127286] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/13/2015] [Indexed: 11/18/2022] Open
Abstract
Cementum Protein 1 (CEMP1) is a key regulator of cementogenesis. CEMP1 promotes cell attachment, differentiation, deposition rate, composition, and morphology of hydroxyapatite crystals formed by human cementoblastic cells. Its expression is restricted to cementoblasts and progenitor cell subpopulations present in the periodontal ligament. CEMP1 transfection into non-osteogenic cells such as adult human gingival fibroblasts results in differentiation of these cells into a “mineralizing” cell phenotype. Other studies have shown evidence that CEMP1 could have a therapeutic potential for the treatment of bone defects and regeneration of other mineralized tissues. To better understand CEMP1’s biological effects in vitro we investigated the consequences of its expression in human gingival fibroblasts (HGF) growing in non-mineralizing media by comparing gene expression profiles. We identified several mRNAs whose expression is modified by CEMP1 induction in HGF cells. Enrichment analysis showed that several of these newly expressed genes are involved in oncogenesis. Our results suggest that CEMP1 causes the transformation of HGF and NIH3T3 cells. CEMP1 is overexpressed in cancer cell lines. We also determined that the region spanning the CEMP1 locus is commonly amplified in a variety of cancers, and finally we found significant overexpression of CEMP1 in leukemia, cervix, breast, prostate and lung cancer. Our findings suggest that CEMP1 exerts modulation of a number of cellular genes, cellular development, cellular growth, cell death, and cell cycle, and molecules associated with cancer.
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Affiliation(s)
- Mercedes Bermúdez
- Laboratorio de Biología Periodontal, Facultad de Odontología, Universidad Nacional Autónoma de México, Mexico City, México
| | | | | | - Margarita Zeichner-David
- Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States of America
| | - Higinio Arzate
- Laboratorio de Biología Periodontal, Facultad de Odontología, Universidad Nacional Autónoma de México, Mexico City, México
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Gagliardi PA, di Blasio L, Puliafito A, Seano G, Sessa R, Chianale F, Leung T, Bussolino F, Primo L. PDK1-mediated activation of MRCKα regulates directional cell migration and lamellipodia retraction. ACTA ACUST UNITED AC 2014; 206:415-34. [PMID: 25092657 PMCID: PMC4121984 DOI: 10.1083/jcb.201312090] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Directional cell migration is of paramount importance in both physiological and pathological processes, such as development, wound healing, immune response, and cancer invasion. Here, we report that 3-phosphoinositide-dependent kinase 1 (PDK1) regulates epithelial directional migration and invasion by binding and activating myotonic dystrophy kinase-related CDC42-binding kinase α (MRCKα). We show that the effect of PDK1 on cell migration does not involve its kinase activity but instead relies on its ability to bind membrane phosphatidylinositol (3,4,5)-trisphosphate. Upon epidermal growth factor (EGF) stimulation, PDK1 and MRCKα colocalize at the cell membrane in lamellipodia. We demonstrate that PDK1 positively modulates MRCKα activity and drives its localization within lamellipodia. Likewise, the retraction phase of lamellipodia is controlled by PDK1 through an MRCKα-dependent mechanism. In summary, we discovered a functional pathway involving PDK1-mediated activation of MRCKα, which links EGF signaling to myosin contraction and directional migration.
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Affiliation(s)
- Paolo Armando Gagliardi
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Laura di Blasio
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Alberto Puliafito
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Giorgio Seano
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Roberto Sessa
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Federica Chianale
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Thomas Leung
- Institute of Molecular and Cell Biology, A-STAR, Singapore 138673, Singapore
| | - Federico Bussolino
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, ItalyDepartment of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
| | - Luca Primo
- Department of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, ItalyDepartment of Oncology and Center for Molecular Systems Biology, University of Turin, Turin 10060, Italy Laboratory of Cell Migration, Candiolo Cancer Institute FPO-IRCCS, Candiolo 10060, Italy
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von der Heyde S, Bender C, Henjes F, Sonntag J, Korf U, Beißbarth T. Boolean ErbB network reconstructions and perturbation simulations reveal individual drug response in different breast cancer cell lines. BMC SYSTEMS BIOLOGY 2014; 8:75. [PMID: 24970389 PMCID: PMC4087127 DOI: 10.1186/1752-0509-8-75] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 06/10/2014] [Indexed: 12/19/2022]
Abstract
Background Despite promising progress in targeted breast cancer therapy, drug resistance remains challenging. The monoclonal antibody drugs trastuzumab and pertuzumab as well as the small molecule inhibitor erlotinib were designed to prevent ErbB-2 and ErbB-1 receptor induced deregulated protein signalling, contributing to tumour progression. The oncogenic potential of ErbB receptors unfolds in case of overexpression or mutations. Dimerisation with other receptors allows to bypass pathway blockades. Our intention is to reconstruct the ErbB network to reveal resistance mechanisms. We used longitudinal proteomic data of ErbB receptors and downstream targets in the ErbB-2 amplified breast cancer cell lines BT474, SKBR3 and HCC1954 treated with erlotinib, trastuzumab or pertuzumab, alone or combined, up to 60 minutes and 30 hours, respectively. In a Boolean modelling approach, signalling networks were reconstructed based on these data in a cell line and time course specific manner, including prior literature knowledge. Finally, we simulated network response to inhibitor combinations to detect signalling nodes reflecting growth inhibition. Results The networks pointed to cell line specific activation patterns of the MAPK and PI3K pathway. In BT474, the PI3K signal route was favoured, while in SKBR3, novel edges highlighted MAPK signalling. In HCC1954, the inferred edges stimulated both pathways. For example, we uncovered feedback loops amplifying PI3K signalling, in line with the known trastuzumab resistance of this cell line. In the perturbation simulations on the short-term networks, we analysed ERK1/2, AKT and p70S6K. The results indicated a pathway specific drug response, driven by the type of growth factor stimulus. HCC1954 revealed an edgetic type of PIK3CA-mutation, contributing to trastuzumab inefficacy. Drug impact on the AKT and ERK1/2 signalling axes is mirrored by effects on RB and RPS6, relating to phenotypic events like cell growth or proliferation. Therefore, we additionally analysed RB and RPS6 in the long-term networks. Conclusions We derived protein interaction models for three breast cancer cell lines. Changes compared to the common reference network hint towards individual characteristics and potential drug resistance mechanisms. Simulation of perturbations were consistent with the experimental data, confirming our combined reverse and forward engineering approach as valuable for drug discovery and personalised medicine.
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Affiliation(s)
| | | | | | | | | | - Tim Beißbarth
- Statistical Bioinformatics, Department of Medical Statistics, University Medical Center Göttingen, Humboldtallee 32, 37073 Göttingen, Germany.
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Köhler A, Demir Ü, Kickstein E, Krauss S, Aigner J, Aranda-Orgillés B, Karagiannidis AI, Achmüller C, Bu H, Wunderlich A, Schweiger MR, Schaefer G, Schweiger S, Klocker H, Schneider R. A hormone-dependent feedback-loop controls androgen receptor levels by limiting MID1, a novel translation enhancer and promoter of oncogenic signaling. Mol Cancer 2014; 13:146. [PMID: 24913494 PMCID: PMC4074869 DOI: 10.1186/1476-4598-13-146] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/30/2014] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND High androgen receptor (AR) level in primary tumour predicts increased prostate cancer (PCa)-specific mortality. Furthermore, activations of the AR, PI3K, mTOR, NFκB and Hedgehog (Hh) signaling pathways are involved in the fatal development of castration-resistant prostate cancer during androgen ablation therapy. MID1, a negative regulator of the tumor-suppressor PP2A, is known to promote PI3K, mTOR, NFκB and Hh signaling. Here we investigate the interaction of MID1 and AR. METHODS AR and MID1 mRNA and protein levels were measured by qPCR, Western blot and immunohistochemistry. Co-immunoprecipitation followed by PCR and RNA-pull-down followed by Western blot was used to investigate protein-mRNA interaction, chromatin-immunoprecipitation followed by next-generation sequencing for identification of AR chromatin binding sites. AR transcriptional activity and activity of promoter binding sites for AR were analyzed by reporter gene assays. For knockdown or overexpression of proteins of interest prostate cancer cells were transfected with siRNA or expression plasmids, respectively. RESULTS The microtubule-associated MID1 protein complex associates with AR mRNA via purine-rich trinucleotide repeats, expansions of which are known to correlate with ataxia and cancer. The level of MID1 directly correlates with the AR protein level in PCa cells. Overexpression of MID1 results in a several fold increase in AR protein and activity without major changes in mRNA-levels, whereas siRNA-triggered knockdown of MID1 mRNA reduces AR-protein levels significantly. Upregulation of AR protein by MID1 occurs via increased translation as no major changes in AR protein stability could be observed. AR on the other hand, regulates MID1 via several functional AR binding sites in the MID1 gene, and, in the presence of androgens, exerts a negative feedback loop on MID1 transcription. Thus, androgen withdrawal increases MID1 and concomitantly AR-protein levels. In line with this, MID1 is significantly over-expressed in PCa in a stage-dependent manner. CONCLUSION Promotion of AR, in addition to enhancement of the Akt-, NFκB-, and Hh-pathways by sustained MID1-upregulation during androgen deprivation therapy provides a powerful proliferative scenario for PCa progression into castration resistance. Thus MID1 represents a novel, multi-faceted player in PCa and a promising target to treat castration resistant prostate cancer.
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Affiliation(s)
- Andrea Köhler
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Ümmühan Demir
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Eva Kickstein
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Sybille Krauss
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
- Present address: German Center for Neurodegenerative Diseases (DZNE), Biomedical Center (BMZ1), Building 344, 53127 Bonn, Germany
| | - Johanna Aigner
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | | | - Antonios I Karagiannidis
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Clemens Achmüller
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Huajie Bu
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Andrea Wunderlich
- Institute of Vertebrate Genetics, Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Michal-Ruth Schweiger
- Institute of Vertebrate Genetics, Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Georg Schaefer
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
- Department of Pathology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Susann Schweiger
- Universitätsmedizin Mainz, Institute for Human Genetics, 55131 Mainz, Germany
- Division of Medical Sciences, Medical School, DD1 9SY Dundee, UK
| | - Helmut Klocker
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Rainer Schneider
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
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Arsenic R. Immunohistochemical analysis of PDK1 expression in breast cancer. Diagn Pathol 2014; 9:82. [PMID: 24739482 PMCID: PMC4005628 DOI: 10.1186/1746-1596-9-82] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 04/03/2014] [Indexed: 12/02/2022] Open
Abstract
Background 3-phosphoinositide-dependent protein kinase-1 (PDK1) functions downstream of phosphoinositide 3-kinase (PIK3) and activates members of the AGC family of protein kinases that are known to play crucial roles in physiological processes associated with cell metabolism, growth, proliferation and survival. Changes in the expression and activity of PDK1 and several AGC kinases have been linked to human disease, including cancer. Methods We used immunohistochemical analysis to determine PDK1 expression in 241 tumors from patients with breast cancer in which we had previously analyzed PIK3CA mutation status. Results Moderate or high expression of PDK1 was observed in 213 of the 241 cases (88%). There was no correlation between PIK3CA mutation status and PDK1 overexpression. Conclusion Our findings indicate that PDK1 is independently activated in breast cancer and not only as part of the PIK3CA pathway, suggesting that PDK1 plays a specific and distinct role from the canonical PIK3/Akt pathway and promotes oncogenesis independently of AKT. Our data implicate PDK-1 and downstream components of the PDK-1 signaling pathway as promising therapeutic targets for the treatment of breast cancer.
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Affiliation(s)
- Ruza Arsenic
- Institute of Pathology Charité, University Hospital Berlin, 10117 Berlin, Germany.
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Targeting the PI3K/AKT/mTOR pathway in estrogen receptor-positive breast cancer. Cancer Treat Rev 2014; 40:862-71. [PMID: 24774538 DOI: 10.1016/j.ctrv.2014.03.004] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 02/08/2023]
Abstract
Approximately 70-75% of breast cancers express the estrogen receptor (ER), indicating a level of dependence on estrogen for growth. Endocrine therapy is an important class of target-directed therapy that blocks the growth-promoting effects of estrogen via ER. Although endocrine therapy continues to be the cornerstone of effective treatment of ER-positive (ER+) breast cancer, many patients with advanced ER+ breast cancer encounter de novo or acquired resistance and require more aggressive treatment such as chemotherapy. Novel approaches are needed to augment the benefit of existing endocrine therapies by prolonging time to disease progression, preventing or overcoming resistance, and delaying the use of chemotherapy. The phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a key intracellular signaling system that drives cellular growth and survival; hyperactivation of this pathway is implicated in the tumorigenesis of ER+ breast cancer and in resistance to endocrine therapy. Moreover, preclinical and clinical evidence show that PI3K/AKT/mTOR pathway inhibition can augment the benefit of endocrine therapy in ER+ breast cancer, from the first-line setting and beyond. This article will review the fundamental role of the PI3K/AKT/mTOR pathway in driving ER+ breast tumors, and its inherent interdependence with ER signaling. In addition, ongoing strategies to combine PI3K/AKT/mTOR pathway inhibitors with endocrine therapy for improved clinical outcomes, and methods to identify patient populations that would benefit most from inhibition of the PI3K/AKT/mTOR pathway, will be evaluated.
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Huemer F, Bartsch R, Gnant M. The PI3K/AKT/MTOR Signaling Pathway: The Role of PI3K and AKT Inhibitors in Breast Cancer. CURRENT BREAST CANCER REPORTS 2014. [DOI: 10.1007/s12609-014-0139-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zhu B, Ferry CH, Blazanin N, Bility MT, Khozoie C, Kang BH, Glick AB, Gonzalez FJ, Peters JM. PPARβ/δ promotes HRAS-induced senescence and tumor suppression by potentiating p-ERK and repressing p-AKT signaling. Oncogene 2013; 33:5348-59. [PMID: 24213576 PMCID: PMC4017002 DOI: 10.1038/onc.2013.477] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 09/23/2013] [Accepted: 10/08/2013] [Indexed: 12/16/2022]
Abstract
Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) inhibits skin tumorigenesis through mechanisms that may be dependent on HRAS signaling. The present study examined the hypothesis that PPARβ/δ promotes HRAS-induced senescence resulting in suppression of tumorigenesis. PPARβ/δ expression increased p-ERK and decreased p-AKT activity. Increased p-ERK activity results from the dampened HRAS-induced negative feedback response mediated in part through transcriptional upregulation of RAS guanyl-releasing protein 1 (RASGRP1) by PPARβ/δ. Decreased p-AKT activity results from repression of integrin-linked kinase (ILK) and phosphoinositide-dependent protein kinase-1 (PDPK1) expression. Decreased p-AKT activity in turn promotes cellular senescence through upregulation of p53 and p27 expression. Both over-expression of RASGRP1 and shRNA-mediated knockdown of ILK partially restore cellular senescence in Pparβ/δ-null cells. Higher PPARβ/δ expression is also correlated with increased senescence observed in human benign neurofibromas and colon adenoma lesions in vivo. These results demonstrate that PPARβ/δ promotes senescence to inhibit tumorigenesis and provide new mechanistic insights into HRAS-induced cellular senescence.
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Affiliation(s)
- B Zhu
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - C H Ferry
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - N Blazanin
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - M T Bility
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - C Khozoie
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - B-H Kang
- Preclinical Research Center, Chemon, Yongin-Si, Korea
| | - A B Glick
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - F J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, Bethesda, MD, USA
| | - J M Peters
- Department of Veterinary and Biomedical Sciences, The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
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Tan J, Li Z, Lee PL, Guan P, Aau MY, Lee ST, Feng M, Lim CZ, Lee EYJ, Wee ZN, Lim YC, Karuturi RKM, Yu Q. PDK1 signaling toward PLK1-MYC activation confers oncogenic transformation, tumor-initiating cell activation, and resistance to mTOR-targeted therapy. Cancer Discov 2013; 3:1156-71. [PMID: 23887393 DOI: 10.1158/2159-8290.cd-12-0595] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
UNLABELLED Although 3-phosphoinositide-dependent protein kinase-1 (PDK1) has been predominately linked to the phosphoinositide 3-kinase (PI3K)-AKT pathway, it may also evoke additional signaling outputs to promote tumorigenesis. Here, we report that PDK1 directly induces phosphorylation of Polo-like kinase 1 (PLK1), which in turn induces MYC phosphorylation and protein accumulation. We show that PDK1-PLK1-MYC signaling is critical for cancer cell growth and survival, and small-molecule inhibition of PDK1/PLK1 provides an effective approach for therapeutic targeting of MYC dependency. Intriguingly, PDK1-PLK1-MYC signaling induces an embryonic stem cell-like gene signature associated with aggressive tumor behaviors and is a robust signaling axis driving cancer stem cell (CSC) self-renewal. Finally, we show that a PLK1 inhibitor synergizes with an mTOR inhibitor to induce synergistic antitumor effects in colorectal cancer by antagonizing compensatory MYC induction. These findings identify a novel pathway in human cancer and CSC activation and provide a therapeutic strategy for targeting MYC-associated tumorigenesis and therapeutic resistance. SIGNIFICANCE This work identifies PDK1–PLK1-MYC signaling as a new oncogenic pathway driving oncogenic transformation and CSC self-renewal. Targeted inhibition of PDK1/PLK1 is robust in targeting MYC dependency in cancer cells. Thus, our findings provide important insights into cancer and CSC biology and have significant therapeutic implications.
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Affiliation(s)
- Jing Tan
- 1Cancer Therapeutics and Stratified Oncology, 2Information and Mathematical Science, Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Biopolis; 3Graduate School for Integrative Sciences and Engineering; 4Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore; and 5Cancer and Stem Cell Biology, DUKE-NUS Graduate Medical School of Singapore, Singapore
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Genetic inactivation or pharmacological inhibition of Pdk1 delays development and inhibits metastasis of Braf(V600E)::Pten(-/-) melanoma. Oncogene 2013; 33:4330-9. [PMID: 24037523 PMCID: PMC3955742 DOI: 10.1038/onc.2013.383] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/18/2013] [Accepted: 07/26/2013] [Indexed: 12/13/2022]
Abstract
Phosphoinositide-dependent kinase-1 (PDK1) is a serine/threonine protein kinase that phosphorylates members of the conserved AGC kinase superfamily, including AKT and protein kinase C (PKC), and is implicated in important cellular processes including survival, metabolism and tumorigenesis. In large cohorts of nevi and melanoma samples, PDK1 expression was significantly higher in primary melanoma, compared with nevi, and was further increased in metastatic melanoma. PDK1 expression suffices for its activity, owing to auto-activation, or elevated phosphorylation by phosphoinositide 3'-OH-kinase (PI3K). Selective inactivation of Pdk1 in the melanocytes of Braf(V600E)::Pten(-/-) or Braf(V600E)::Cdkn2a(-/-)::Pten(-/-) mice delayed the development of pigmented lesions and melanoma induced by systemic or local administration of 4-hydroxytamoxifen. Melanoma invasion and metastasis were significantly reduced or completely prevented by Pdk1 deletion. Administration of the PDK1 inhibitor GSK2334470 (PDKi) effectively delayed melanomagenesis and metastasis in Braf(V600E)::Pten(-/-) mice. Pdk1(-/-) melanomas exhibit a marked decrease in the activity of AKT, P70S6K and PKC. Notably, PDKi was as effective in inhibiting AGC kinases and colony forming efficiency of melanoma with Pten wild-type (WT) genotypes. Gene expression analyses identified Pdk1-dependent changes in FOXO3a-regulated genes, and inhibition of FOXO3a restored proliferation and colony formation of Pdk1(-/-) melanoma cells. Our studies provide direct genetic evidence for the importance of PDK1, in part through FOXO3a-dependent pathway, in melanoma development and progression.
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Fu X, Osborne CK, Schiff R. Biology and therapeutic potential of PI3K signaling in ER+/HER2-negative breast cancer. Breast 2013; 22 Suppl 2:S12-8. [PMID: 24011769 DOI: 10.1016/j.breast.2013.08.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PI3K is a central node mediating growth factor receptor signaling. With its downstream effectors such as AKT and mTOR, and its crosstalk with the RAS/RAF/MEK/MAPK pathway, it plays a vital role in cancer cell proliferation, metabolism, and survival. Recent breast cancer (BC) molecular portraits delineate PI3K as the most frequently altered pathway, with recurrent PIK3CA mutations mostly found in the luminal subtypes of BC. The transcriptomic and proteomic signatures of PI3K pathway activation associate with reduced estrogen receptor α (ER) levels and activity, and with the luminal B subtype of BC that has a relatively poor outcome. However, oncogenic transforming PIK3CA mutations have been shown to predict a better outcome in ER+/HER2-negative BC treated with endocrine therapy. In this review, we summarize the recent findings in the cause-and-effect of PI3K pathway aberration and endocrine sensitivity, especially the crosstalk with the ER pathway. Potential therapeutic approaches based on these findings are also discussed.
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Affiliation(s)
- Xiaoyong Fu
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
Phospholipases are enzymes that use phospholipids as substrate and are classified in three major classes A, C and D based on the reaction they catalyse. Phosphatidylinositol-specific Phospholipase C enzymes utilize phosphatidylinositol 4,5-bisphosphate as substrate and cleave the bond between the glycerol and the phosphate to produce important second messenger such as inositol trisphosphate and diacylglycerol. The Phospholipase C members are the most well-known phospholipases for their role in lipid signalling and cell proliferation and comprise 13 isoforms classified in 6 distinct sub-families. In particular, signalling activated by Phospholipase C γ, mostly activated by receptor and non-receptor tyrosine kinases, is well characterized in different cell systems. Increasing evidence suggest that Phospholipase C γ plays a key role in cell migration and invasion. Because of its role in cell growth and invasion, aberrant Phospholipase C γ signalling can contribute to carcinogenesis. A major challenge facing investigators who seek to target Phospholipase C γ directly is the fact that it is considered an "undruggable" protein. Indeed, isoform specificity and toxicity represents a big hurdle in the development of Phospholipase C γ small molecule inhibitors. Therefore, a future development in the field could be the identification of interacting partners as therapeutic targets that could be more druggable than Phospholipase C γ.
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Affiliation(s)
- Rossano Lattanzio
- Aging Research Centre, G. d'Annunzio University Foundation, 66013 Chieti, Italy.
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78
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Fyffe C, Falasca M. 3-Phosphoinositide-dependent protein kinase-1 as an emerging target in the management of breast cancer. Cancer Manag Res 2013; 5:271-80. [PMID: 24039447 PMCID: PMC3771848 DOI: 10.2147/cmar.s35026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It should be noted that 3-phosphoinositide-dependent protein kinase-1 (PDK1) is a protein encoded by the PDPK1 gene, which plays a key role in the signaling pathways activated by several growth factors and hormones. PDK1 is a crucial kinase that functions downstream of phosphoinositide 3-kinase activation and activates members of the AGC family of protein kinases, such as protein kinase B (Akt), protein kinase C (PKC), p70 ribosomal protein S6 kinases, and serum glucocorticoid-dependent kinase, by phosphorylating serine/threonine residues in the activation loop. AGC kinases are known to play crucial roles in regulating physiological processes relevant to metabolism, growth, proliferation, and survival. Changes in the expression and activity of PDK1 and several AGC kinases have been linked to human diseases including cancer. Recent data have revealed that the alteration of PDK1 is a critical component of oncogenic phosphoinositide 3-kinase signaling in breast cancer, suggesting that inhibition of PDK1 can inhibit breast cancer progression. Indeed, PDK1 is highly expressed in a majority of human breast cancer cell lines and both PDK1 protein and messenger ribonucleic acid are overexpressed in a majority of human breast cancers. Furthermore, overexpression of PDK1 is sufficient to transform mammary epithelial cells. PDK1 plays an essential role in regulating cell migration, especially in the context of phosphatase and tensin homologue deficiency. More importantly, downregulation of PDK1 levels inhibits migration and experimental metastasis of human breast cancer cells. Thus, targeting PDK1 may be a valuable anticancer strategy that may improve the efficacy of chemotherapeutic strategies in breast cancer patients. In this review, we summarize the evidence that has been reported to support the idea that PDK1 may be a key target in breast cancer management.
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Affiliation(s)
- Chanse Fyffe
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Inositide Signallling Group, London, UK
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79
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Ziemba BP, Pilling C, Calleja V, Larijani B, Falke JJ. The PH domain of phosphoinositide-dependent kinase-1 exhibits a novel, phospho-regulated monomer-dimer equilibrium with important implications for kinase domain activation: single-molecule and ensemble studies. Biochemistry 2013; 52:4820-9. [PMID: 23745598 DOI: 10.1021/bi400488f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphoinositide-dependent kinase-1 (PDK1) is an essential master kinase recruited to the plasma membrane by the binding of its C-terminal PH domain to the signaling lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3). Membrane binding leads to PDK1 phospho-activation, but despite the central role of PDK1 in signaling and cancer biology, this activation mechanism remains poorly understood. PDK1 has been shown to exist as a dimer in cells, and one crystal structure of its isolated PH domain exhibits a putative dimer interface. It has been proposed that phosphorylation of PH domain residue T513 (or the phospho-mimetic T513E mutation) may regulate a novel PH domain dimer-monomer equilibrium, thereby converting an inactive PDK1 dimer to an active monomer. However, the oligomeric states of the PH domain on the membrane have not yet been determined, nor whether a negative charge at position 513 is sufficient to regulate its oligomeric state. This study investigates the binding of purified wild-type (WT) and T513E PDK1 PH domains to lipid bilayers containing the PIP3 target lipid, using both single-molecule and ensemble measurements. Single-molecule analysis of the brightness of the fluorescent PH domain shows that the PIP3-bound WT PH domain on membranes is predominantly dimeric while the PIP3-bound T513E PH domain is monomeric, demonstrating that negative charge at the T513 position is sufficient to dissociate the PH domain dimer and is thus likely to play a central role in PDK1 monomerization and activation. Single-molecule analysis of two-dimensional (2D) diffusion of PH domain-PIP3 complexes reveals that the dimeric WT PH domain diffuses at the same rate as a single lipid molecule, indicating that only one of its two PIP3 binding sites is occupied and there is little penetration of the protein into the bilayer as observed for other PH domains. The 2D diffusion of T513E PH domain is slower, suggesting the negative charge disrupts local structure in a way that allows deeper insertion of the protein into the viscous bilayer, thereby increasing the diffusional friction. Ensemble measurements of PH domain affinity for PIP3 on plasma membrane-like bilayers reveal that the dimeric WT PH domain possesses a one order of magnitude higher target membrane affinity than the previously characterized monomeric PH domains, consistent with a dimerization-triggered, allosterically enhanced affinity for one PIP3 molecule (a much larger affinity enhancement would be expected for dimerization-triggered binding to two PIP3 molecules). The monomeric T513E PDK1 PH domain, like other monomeric PH domains, exhibits a PIP3 affinity and bound state lifetime that are each 1 order of magnitude lower than those of the dimeric WT PH domain, which is predicted to facilitate release of activated, monomeric PDK1 to the cytoplasm. Overall, the study yields the first molecular picture of PH domain regulation via electrostatic control of dimer-monomer conversion.
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Affiliation(s)
- Brian P Ziemba
- Department of Chemistry and Biochemistry and Molecular Biophysics Program, University of Colorado , Boulder, Colorado 80309-0596, United States
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80
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Tan J, Yu Q. Molecular mechanisms of tumor resistance to PI3K-mTOR-targeted therapy. CHINESE JOURNAL OF CANCER 2013; 32:376-9. [PMID: 23668928 PMCID: PMC3845604 DOI: 10.5732/cjc.012.10287] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Deregulation of the phosphatidylinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signaling pathway occurs frequently in a wide range of human cancers and is a major driving force in tumorigenesis. Thus, small molecules targeting this pathway are under active development as anticancer therapeutics. Although small-molecule inhibitors of the PI3K-mTOR pathway have shown promising clinical efficacy against human cancers, the emergence of drug resistance may limit their success in the clinic. To date, several resistance mechanisms, including both PI3K-dependent and -independent mechanisms, have been described. Here, we summarize the current understanding of resistance mechanisms to PI3K-mTOR inhibitors and discuss potential strategies for overcoming resistance for potential clinical application.
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Affiliation(s)
- Jing Tan
- Genome Institute of Singapore, Agency for Science, Technology and Research, Biopolis, Singapore.
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81
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Rexer BN, Shyr Y, Arteaga CL. Phosphatase and tensin homolog deficiency and resistance to trastuzumab and chemotherapy. J Clin Oncol 2013; 31:2073-5. [PMID: 23650407 DOI: 10.1200/jco.2012.48.5243] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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82
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Myhre S, Lingjærde OC, Hennessy BT, Aure MR, Carey MS, Alsner J, Tramm T, Overgaard J, Mills GB, Børresen-Dale AL, Sørlie T. Influence of DNA copy number and mRNA levels on the expression of breast cancer related proteins. Mol Oncol 2013; 7:704-18. [PMID: 23562353 DOI: 10.1016/j.molonc.2013.02.018] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 02/11/2013] [Accepted: 02/25/2013] [Indexed: 11/26/2022] Open
Abstract
For a panel of cancer related proteins, the aim was to shed light on which molecular level the expression of each protein was mainly regulated in breast tumors, and to investigate whether differences in regulation were reflected in different molecular subtypes. DNA, mRNA and protein lysates from 251 breast tumor specimens were analyzed using appropriate microarray technologies. Data from all three levels were available for 52 proteins selected for their known involvement in cancer, primarily through the PI3K/Akt pathway. For every protein, in cis Spearman rank correlations between the three molecular levels were calculated across all samples and within each intrinsic gene expression subtype, enabling 63 comparisons altogether due to multiple gene probes matching to single proteins. Subtype-specific relationships between the three molecular levels were studied by calculating the variance of subtype-specific correlation and differences between overall and average subtype-specific correlation. The findings were validated in an external dataset comprising 703 breast tumor specimens. The proteins were sorted into four groups based on the calculated rank correlation values between the three molecular levels. Group A consisted of eight proteins with significant correlation between DNA copy number levels and mRNA expression, and between mRNA expression and protein expression (Bonferroni adjusted p < 0.05). Group B consisted of 14 proteins with significant correlation between mRNA expression and protein expression. Group C consisted of 15 proteins with significant correlation between copy number levels and mRNA expression. For the remaining 25 proteins (group D), no significant correlations was observed. Stratification of tumors according to intrinsic subtype enabled identification of positive correlations between copy number levels, mRNA and protein expression that were undetectable when considering the entire sample set. Protein pairings that either demonstrated high variance in correlation values between subtypes, or between subtypes and the total dataset were studied in particular. The protein expression of cleaved caspase 7 was most highly expressed, and correlated highest to CASP7 gene expression within the basal-like subtype, accompanied by the lowest amounts of hsa-miR-29c. Luminal A-like subtype demonstrated highest amounts of hsa-miR-29c (a miRNA with a putative target sequence in CASP7 mRNA), low expression of cleaved caspase 7 and low correlation to CASP7 gene expression. Such pattern might be an indication of hsa-miR-29c miRNA functioning as a repressor of translation of CASP7 within the luminal-A subtype. Across the entire cohort no correlation was found between CCNB1 copy number and gene expression. However, within most gene intrinsic subtypes, mRNA and protein expression of cyclin B1 was found positively correlated to copy number data, suggesting that copy number can affect the overall expression of this protein. Aberrations of cyclin B1 copy number also identified patients with reduced overall survival within each subtype. Based on correlation between the three molecular levels, genes and their products could be sorted into four groups for which the expression was likely to be regulated at different molecular levels. Further stratification suggested subtype-specific regulation that was not evident across the entire sample set.
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Affiliation(s)
- Simen Myhre
- Department of Genetics, Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, N-0310 Oslo, Norway.
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83
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3-phosphoinositide-dependent kinase 1 controls breast tumor growth in a kinase-dependent but Akt-independent manner. Neoplasia 2013; 14:719-31. [PMID: 22952425 DOI: 10.1593/neo.12856] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 06/25/2012] [Accepted: 06/28/2012] [Indexed: 01/09/2023] Open
Abstract
3-phosphoinositide-dependent protein kinase 1 (PDK1) is the pivotal element of the phosphatidylinositol 3 kinase (PI3K) signaling pathway because it phosphorylates Akt/PKB through interactions with phosphatidylinositol 3,4,5 phosphate. Recent data indicate that PDK1 is overexpressed in many breast carcinomas and that alterations of PDK1 are critical in the context of oncogenic PI3K activation. However, the role of PDK1 in tumor progression is still controversial. Here, we show that PDK1 is required for anchorage-independent and xenograft growth of breast cancer cells harboring either PI3KCA or KRAS mutations. In fact, PDK1 silencing leads to increased anoikis, reduced soft agar growth, and pronounced apoptosis inside tumors. Interestingly, these phenotypes are reverted by PDK1 wild-type but not kinase-dead mutant, suggesting a relevant role of PDK1 kinase activity, even if PDK1 is not relevant for Akt activation here. Indeed, the expression of constitutively active forms of Akt in PDK1 knockdown cells is unable to rescue the anchorage-independent growth. In addition, Akt down-regulation and pharmacological inhibition do not inhibit the effects of PDK1 overexpression. In summary, these results suggest that PDK1 may contribute to breast cancer, even in the absence of PI3K oncogenic mutations and through both Akt-dependent and Akt-independent mechanisms.
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84
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Jones N, Bonnet F, Sfar S, Lafitte M, Lafon D, Sierankowski G, Brouste V, Banneau G, Tunon de Lara C, Debled M, MacGrogan G, Longy M, Sevenet N. Comprehensive analysis of PTEN status in breast carcinomas. Int J Cancer 2013; 133:323-34. [PMID: 23319441 DOI: 10.1002/ijc.28021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 12/17/2012] [Indexed: 02/01/2023]
Abstract
PTEN plays a well-established role in the negative regulation of the PI3K pathway, which is frequently activated in several cancer types, including breast cancer. A nuclear function in the maintenance of chromosomal stability has been proposed for PTEN but is yet to be clearly defined. In order to improve understanding of the role of PTEN in mammary tumorigenesis in terms of a possible gene dosage effect, its PI3K pathway function and its association with p53, we undertook comprehensive analysis of PTEN status in 135 sporadic invasive ductal carcinomas. Four PTEN status groups were defined; complete loss (19/135, 14%), reduced copy number (19/135, 14%), normal (86/135, 64%) and complex (11/135, 8%). Whereas the PTEN complete loss status was significantly associated with estrogen receptor (ER) negativity (p=0.006) and in particular the basal-like phenotype (p<0.0001), a reduced PTEN copy number was not associated with hormone receptor status or a particular breast cancer subtype. Overall, PI3K pathway alteration was suggested to be involved in 59% (79/134) of tumors as assessed by human epidermal growth factor receptor 2 overexpression, PIK3CA mutation or a complete loss of PTEN. A complex PTEN status was identified in a tumor subgroup which displayed a specific, complex DNA profile at the PTEN locus with a strikingly similar highly rearranged pan-genomic profile. All of these tumors had relapsed and were associated with a poorer prognosis in the context of node negative disease (p=1.4 × 10(-13) ) thus may represent a tumor subgroup with a common molecular alteration which could be targeted to improve clinical outcome.
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Affiliation(s)
- Natalie Jones
- INSERM U916 VINCO, University of Bordeaux, Institut Bergonié, Bordeaux, France
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85
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Pires MM, Hopkins BD, Saal LH, Parsons RE. Alterations of EGFR, p53 and PTEN that mimic changes found in basal-like breast cancer promote transformation of human mammary epithelial cells. Cancer Biol Ther 2013; 14:246-53. [PMID: 23291982 PMCID: PMC3595307 DOI: 10.4161/cbt.23297] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Breast cancer can be classified into different molecular subtypes with varying clinical and pathological characteristics. The basal-like breast cancer subtype represents one of the most aggressive and lethal types of breast cancer, and due to poor mechanistic understanding, it lacks targeted therapy. Many basal-like breast cancer patient samples display alterations of established drivers of cancer development, including elevated expression of EGFR, p53 inactivating mutations and loss of expression of the tumor suppressor PTEN; however, their contribution to human basal-like breast cancer pathogenesis remains ill-defined. Using non-transformed human mammary epithelial cells, we set out to determine whether altering EGFR, p53 and PTEN in different combinations could contribute to basal-like breast cancer progression through transformation of cells. Altering PTEN in combination with either p53 or EGFR in contrast to any of the single alterations caused increased growth of transformed colonies in soft agar. Concomitantly modifying all three genes led to the highest rate of cellular proliferation and the greatest degree of anchorage-independent colony formation. Results from our effort to engineer a model of BBC expressing alterations of EGFR, p53 and PTEN suggest that these changes are cooperative and likely play a causal role in basal-like breast cancer pathogenesis. Consideration should be given to targeting EGFR and restoring p53 and PTEN signaling simultaneously as a strategy for treatment of this subtype of breast cancer.
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Affiliation(s)
- Maira M Pires
- Institute for Cancer Genetics, Herbert Irving Cancer Center, Columbia University, New York, NY, USA
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86
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The 16p13.3 (PDPK1) Genomic Gain in Prostate Cancer: A Potential Role in Disease Progression. Transl Oncol 2012; 5:453-60. [PMID: 23401739 DOI: 10.1593/tlo.12286] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/18/2012] [Accepted: 09/19/2012] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Prostate cancer (PCa) is a leading cause of cancer death, and distinguishing aggressive from indolent tumors is a major challenge. Identification and characterization of genomic alterations associated with advanced disease can provide new markers of progression and better therapeutic approaches. METHODS We performed fluorescence in situ hybridization to detect the copy number gain of chromosome 16p13.3 in 75 PCa samples including 10 lymph node (LN) metastases and their matched primary tumors, 9 samples of castration-resistant prostate cancer (CRPC), and 46 additional primary PCa specimens with clinicopathologic parameters. RESULTS We detected the gain in 5 of 10 LN metastases and 3 of 5 matched primary tumors, 3 of 9 CRPC samples, and 9 of 46 (20%) primary tumors where the 16p13.3 alteration was associated with high Gleason score and elevated preoperative prostate-specific antigen levels. The level of 16p13.3 gain was higher in LN metastasis and CRPC specimens compared to primary PCa. Chromosome mapping revealed the gain spans PDPK1 encoding the 3-phosphoinositide-dependent protein kinase-1 (PDK1). Knockdown of PDK1 in three PCa cell lines reduced migration without affecting growth and re-expressing PDK1 rescued motility. CONCLUSION Our findings support a prognostic value of the 16p13.3 gain and a role of PDK1 in PCa progression through migration.
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87
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Baxi SM, Tan W, Murphy ST, Smeal T, Yin MJ. Targeting 3-phosphoinoside-dependent kinase-1 to inhibit insulin-like growth factor-I induced AKT and p70 S6 kinase activation in breast cancer cells. PLoS One 2012; 7:e48402. [PMID: 23119004 PMCID: PMC3485233 DOI: 10.1371/journal.pone.0048402] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 09/25/2012] [Indexed: 12/15/2022] Open
Abstract
Binding of IGF to IGF-IR activates PI3K to generate PIP3 which in turn recruits and activates proteins that contain a pleckstrin homology (PH) domain, including AKT and PDK1. PDK1 is highly expressed in breast tumor samples and breast cancer cell lines. Here we demonstrate that targeting PDK1 with the potent and selective PDK1 inhibitor PF-5177624 in the IGF-PI3K pathway blocks breast cancer cell proliferation and transformation. Breast cancer cell lines MCF7 and T47D, representing the luminal ER positive subtype and harboring PIK3CA mutations, were most responsive to IGF-I induction resulting in upregulated AKT and p70S6K phosphorylation via PDK1 activation. PF-5177624 downregulated AKT and p70S6K phosphorylation, blocked cell cycle progression, and decreased cell proliferation and transformation to block IGFR-I induced activation in breast cancer cells. These results may provide insight into clinical strategies for developing an IGFR-I inhibitor and/or a PDK1 inhibitor in luminal breast cancer patients.
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Affiliation(s)
- Sangita M. Baxi
- Oncology Research, Pfizer Worldwide Research and Development, San Diego, California, United States of America
| | - Wei Tan
- Oncology Research, Pfizer Worldwide Research and Development, San Diego, California, United States of America
| | - Sean T. Murphy
- Medicinal Chemistry, Pfizer Worldwide Research and Development, San Diego, California, United States of America
| | - Tod Smeal
- Oncology Research, Pfizer Worldwide Research and Development, San Diego, California, United States of America
| | - Min-Jean Yin
- Oncology Research, Pfizer Worldwide Research and Development, San Diego, California, United States of America
- * E-mail:
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88
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Lee ACH, Ramanujulu PM, Poulsen A, Williams M, Blanchard S, Ma DM, Bonday Z, Goh KL, Goh KC, Goh MK, Wood J, Dymock BW. Thieno[3,2-d]pyrimidin-4(3H)-one derivatives as PDK1 inhibitors discovered by fragment-based screening. Bioorg Med Chem Lett 2012; 22:4023-7. [DOI: 10.1016/j.bmcl.2012.04.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 04/13/2012] [Accepted: 04/17/2012] [Indexed: 11/16/2022]
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89
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Role of phosphatidylinositol-3-kinase pathway in head and neck squamous cell carcinoma. JOURNAL OF ONCOLOGY 2012; 2012:450179. [PMID: 22666248 PMCID: PMC3362130 DOI: 10.1155/2012/450179] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 03/14/2012] [Indexed: 01/04/2023]
Abstract
Activation of the phosphatidylinositol-3-kinase (PI3K) pathway is one of the most frequently observed molecular alterations in many human malignancies, including head and neck squamous cell carcinoma (HNSCC). A growing body of evidence demonstrates the prime importance of the PI3K pathway at each stage of tumorigenesis, that is, tumor initiation, progression, recurrence, and metastasis. Expectedly, targeting the PI3K pathway yields some promising results in both preclinical studies and clinical trials for certain cancer patients. However, there are still many questions that need to be answered, given the complexity of this pathway and the existence of its multiple feedback loops and interactions with other signaling pathways. In this paper, we will summarize recent advances in the understanding of the PI3K pathway role in human malignancies, with an emphasis on HNSCC, and discuss the clinical applications and future direction of this field.
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90
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Raimondi C, Chikh A, Wheeler AP, Maffucci T, Falasca M. A novel regulatory mechanism links PLCγ1 to PDK1. J Cell Sci 2012; 125:3153-63. [PMID: 22454520 DOI: 10.1242/jcs.100511] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) and phospholipase C (PLC)γ1 are two key enzymes in signal transduction that control several intracellular processes. Despite the fact that PLCγ1 has been investigated for several years, the mechanisms of activation of this enzyme are still not completely clear. Similarly, although PDK1 has been mostly investigated for its role in activation of Akt, a crucial enzyme in regulation of several cellular processes, it has become evident recently that the role of PDK1 in physiological and pathological conditions is not limited to Akt activation. Here we demonstrate that PDK1 regulates PLCγ1 activation in a mechanism involving association of the two enzymes and modulation of PLCγ1 tyrosine phosphorylation. We further show that this novel PDK1-PLCγ1 pathway is important for cancer cell invasion. The identification of a PDK1-PLCγ1 pathway reveals the existence of a previously undetected link between two of the most important enzymes in signal transduction. This is likely to have profound consequences for our understanding of several cellular functions that are dependent on phosphoinositides and controlled by PDK1 and PLCγ1.
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Affiliation(s)
- Claudio Raimondi
- Centre for Diabetes, Blizard Institute, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, London, UK
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91
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Blanchard S, Soh CK, Lee CP, Poulsen A, Bonday Z, Goh KL, Goh KC, Goh MK, Pasha MK, Wang H, Williams M, Wood JM, Ethirajulu K, Dymock BW. 2-anilino-4-aryl-8H-purine derivatives as inhibitors of PDK1. Bioorg Med Chem Lett 2012; 22:2880-4. [PMID: 22437109 DOI: 10.1016/j.bmcl.2012.02.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 02/16/2012] [Accepted: 02/20/2012] [Indexed: 01/21/2023]
Abstract
A series of 2-anilino substituted 4-aryl-8H-purines were prepared as potent inhibitors of PDK1, a serine-threonine kinase thought to play a role in the PI3K/Akt signaling pathway, a key mediator of cancer cell growth, survival and tumorigenesis. The synthesis, SAR and ADME properties of this series of compounds are discussed culminating in the discovery of compound 6 which possessed sub-micromolar cell proliferation activity and 65% oral bioavailability in mice.
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Affiliation(s)
- Stéphanie Blanchard
- S*BIO Pte. Ltd, The Capricorn, Singapore Science Park II, Singapore, Singapore.
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92
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Jester BW, Gaj A, Shomin CD, Cox KJ, Ghosh I. Testing the promiscuity of commercial kinase inhibitors against the AGC kinase group using a split-luciferase screen. J Med Chem 2012; 55:1526-37. [PMID: 22257127 DOI: 10.1021/jm201265f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using a newly developed competitive binding assay dependent upon the reassembly of a split reporter protein, we have tested the promiscuity of a panel of reported kinase inhibitors against the AGC group. Many non-AGC targeted kinase inhibitors target multiple members of the AGC group. In general, structurally similar inhibitors consistently exhibited activity toward the same target as well as toward closely related kinases. The inhibition data was analyzed to test the predictive value of either using identity scores derived from residues within 6 Å of the active site or identity scores derived from the entire kinase domain. The results suggest that the active site identity in certain cases may be a stronger predictor of inhibitor promiscuity. The overall results provide general guidelines for establishing inhibitor selectivity as well as for the future design of inhibitors that either target or avoid AGC kinases.
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Affiliation(s)
- Benjamin W Jester
- Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States
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93
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The PKCθ pathway participates in the aberrant accumulation of Fra-1 protein in invasive ER-negative breast cancer cells. Oncogene 2012; 31:4889-97. [PMID: 22286759 DOI: 10.1038/onc.2011.659] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fra-1 is aberrantly expressed in a large number of cancer cells and tissues, and emerging evidence suggests an important role for this Fos family protein in both oncogenesis and the progression or maintenance of many tumour types. Here, we show that the concentration of Fra-1 is high in invasive oestrogen receptor (ER)-negative (ER-) breast cancer cell lines, regardless of their Ras pathway status. All of the ER- cells express high levels of activated PKCθ, and the inhibition of PKCθ activity using RNA interference or the expression of a dominant-negative mutant results in a dramatic reduction in Fra-1 abundance. Conversely, the ectopic expression of constitutively active PKCθ leads to Fra-1 phosphorylation and accumulation in poorly invasive ER+ cells. This accumulation is due to the stabilisation of the Fra-1 protein through PKCθ signalling, whereas other members of the PKC family are ineffective. Both Ste20-related proline-alanine-rich kinase (SPAK) and ERK1/2, whose activities are upregulated by PKCθ, participate in PKCθ-driven Fra-1 stabilisation. Interestingly, their relative contributions appear to be different depending on the cell line studied. ERK1/2 signalling has a major role in ER- MDA-MB-231 cells, whereas Fra-1 accumulation occurs mainly through SPAK signalling in ER- BT549 cells. Fra-1 mutational analysis shows that the phosphorylation of S265, T223 and T230 is critical for PKCθ-driven Fra-1 stabilisation. Phosphorylation of the protein was confirmed using specific antisera against Fra-1 phosphorylated on T223 or S265. In addition, Fra-1 participates in PKCθ-induced cell invasion and is necessary for PKCθ-induced cell migration. In summary, we identified PKCθ signalling as an important regulator of Fra-1 accumulation in ER- breast cancer cells. Moreover, our results suggest that PKCθ could participate in progression of some breast cancers and could be a new therapeutic target.
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94
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Miller TW, Balko JM, Arteaga CL. Phosphatidylinositol 3-kinase and antiestrogen resistance in breast cancer. J Clin Oncol 2011; 29:4452-61. [PMID: 22010023 PMCID: PMC3221526 DOI: 10.1200/jco.2010.34.4879] [Citation(s) in RCA: 304] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 08/04/2011] [Indexed: 12/17/2022] Open
Abstract
Although antiestrogen therapies targeting estrogen receptor (ER) α signaling prevent disease recurrence in the majority of patients with hormone-dependent breast cancer, a significant fraction of patients exhibit de novo or acquired resistance. Currently, the only accepted mechanism linked with endocrine resistance is amplification or overexpression of the ERBB2 (human epidermal growth factor receptor 2 [HER2]) proto-oncogene. Experimental and clinical evidence suggests that hyperactivation of the phosphatidylinositol 3-kinase (PI3K) pathway, the most frequently mutated pathway in breast cancer, promotes antiestrogen resistance. PI3K is a major signaling hub downstream of HER2 and other receptor tyrosine kinases. PI3K activates several molecules involved in cell-cycle progression and survival, and in ER-positive breast cancer cells, it promotes estrogen-dependent and -independent ER transcriptional activity. Preclinical tumor models of antiestrogen-resistant breast cancer often remain sensitive to estrogens and PI3K inhibition, suggesting that simultaneous targeting of the PI3K and ER pathways may be most effective. Herein, we review alterations in the PI3K pathway associated with resistance to endocrine therapy, the state of clinical development of PI3K inhibitors, and strategies for the clinical investigation of such drugs in hormone receptor-positive breast cancer.
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Affiliation(s)
- Todd W. Miller
- All authors: Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN
| | - Justin M. Balko
- All authors: Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN
| | - Carlos L. Arteaga
- All authors: Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN
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95
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Miller TW, Rexer BN, Garrett JT, Arteaga CL. Mutations in the phosphatidylinositol 3-kinase pathway: role in tumor progression and therapeutic implications in breast cancer. Breast Cancer Res 2011; 13:224. [PMID: 22114931 PMCID: PMC3315683 DOI: 10.1186/bcr3039] [Citation(s) in RCA: 331] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mutations in genes that constitute the phosphatidylinositol 3-kinase (PI3K) pathway occur in >70% of breast cancers. Clinical and experimental evidence suggest that PI3K pathway activation promotes resistance to some of the current breast cancer therapies. PI3K is a major signaling hub downstream of human epidermal growth factor receptor (HER)2 and other receptor tyrosine kinases. PI3K activates AKT, serum/glucocorticoid regulated kinase (SGK), phosphoinositide-dependent kinase 1 (PDK1), mammalian target of rapamycin (mTOR), and several other molecules involved in cell cycle progression and survival. In estrogen receptor (ER)+ breast cancer cells, PI3K activation promotes estrogen-dependent and -independent ER transcriptional activity, which, in turn, may contribute to anti-estrogen resistance. Activation of this pathway also confers resistance to HER2-targeted therapies. In experimental models of resistance to anti-estrogens and HER2 inhibitors, pharmacological inhibition of PI3K/AKT/mTOR has been shown to overcome drug resistance. Early clinical data suggest that combined inhibition of either HER2 or ER plus inhibition of the PI3K pathway might be an effective strategy for treatment of respective HER2+ and ER+ breast cancers resistant to standard therapies. Here, we review alterations in the PI3K pathway in breast cancer, their association with therapeutic resistance, and the state of clinical development of PI3K pathway inhibitors.
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Affiliation(s)
- Todd W Miller
- Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA
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96
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Yamaguchi H, Yoshida S, Muroi E, Yoshida N, Kawamura M, Kouchi Z, Nakamura Y, Sakai R, Fukami K. Phosphoinositide 3-kinase signaling pathway mediated by p110α regulates invadopodia formation. ACTA ACUST UNITED AC 2011; 193:1275-88. [PMID: 21708979 PMCID: PMC3216328 DOI: 10.1083/jcb.201009126] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Inhibition of p110α or of the downstream PI3K signaling pathway components PDK1 and Akt, as well as phosphoinositide sequestration, blocks invadopodia formation in breast cancer cells. Invadopodia are extracellular matrix–degrading protrusions formed by invasive cancer cells that are thought to function in cancer invasion. Although many invadopodia components have been identified, signaling pathways that link extracellular stimuli to invadopodia formation remain largely unknown. We investigate the role of phosphoinositide 3-kinase (PI3K) signaling during invadopodia formation. We find that in human breast cancer cells, both invadopodia formation and degradation of a gelatin matrix were blocked by treatment with PI3K inhibitors or sequestration of D-3 phosphoinositides. Functional analyses revealed that among the PI3K family proteins, the class I PI3K catalytic subunit p110α, a frequently mutated gene product in human cancers, was selectively involved in invadopodia formation. The expression of p110α with cancerous mutations promoted invadopodia-mediated invasive activity. Furthermore, knockdown or inhibition of PDK1 and Akt, downstream effectors of PI3K signaling, suppressed invadopodia formation induced by p110α mutants. These data suggest that PI3K signaling via p110α regulates invadopodia-mediated invasion of breast cancer cells.
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Affiliation(s)
- Hideki Yamaguchi
- Division of Metastasis and Invasion Signaling, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan.
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97
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Adams JR, Schachter NF, Liu JC, Zacksenhaus E, Egan SE. Elevated PI3K signaling drives multiple breast cancer subtypes. Oncotarget 2011; 2:435-47. [PMID: 21646685 PMCID: PMC3248195 DOI: 10.18632/oncotarget.285] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Most human breast tumors have mutations that elevate signaling through a key metabolic pathway that is induced by insulin and a number of growth factors. This pathway serves to activate an enzyme known as phosphatidylinositol 3' kinase (PI3K) as well as to regulate proteins that signal in response to lipid products of PI3K. The specific mutations that activate this pathway in breast cancer can occur in genes coding for tyrosine kinase receptors, adaptor proteins linked to PI3K, catalytic and regulatory subunits of PI3K, serine/threonine kinases that function downstream of PI3K, and also phosphatidylinositol 3' phosphatase tumor suppressors that function to antagonize this pathway. While each genetic change results in net elevation of PI3K pathway signaling, and all major breast cancer subtypes show pathway activation, the specific mutation(s) involved in any one tumor may play an important role in defining tumor subtype, prognosis and even sensitivity to therapy. Here, we describe mouse models of breast cancer with elevated PI3K signaling, and how they may be used to guide development of novel therapeutics.
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Affiliation(s)
- Jessica R. Adams
- 1 Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 101 College St., East Tower
- 2 The Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nathan F. Schachter
- 1 Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 101 College St., East Tower
- 2 The Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jeff C. Liu
- 3 Division of Cell and Molecular Biology, Toronto General Research Institute–University Health Network, Toronto, Ontario, Canada
| | - Eldad Zacksenhaus
- 3 Division of Cell and Molecular Biology, Toronto General Research Institute–University Health Network, Toronto, Ontario, Canada
- 4 The Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Sean E. Egan
- 1 Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 101 College St., East Tower
- 2 The Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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98
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Andreopoulou E. The PI3K/AKT/mTOR Signaling Pathway: Implications in the Treatment of Breast Cancer. CURRENT BREAST CANCER REPORTS 2011. [DOI: 10.1007/s12609-010-0038-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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99
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Wang C, Bian Z, Wei D, Zhang JG. miR-29b regulates migration of human breast cancer cells. Mol Cell Biochem 2011; 352:197-207. [DOI: 10.1007/s11010-011-0755-z] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Accepted: 02/17/2011] [Indexed: 12/19/2022]
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100
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Wu J, Dauchy RT, Tirrell PC, Wu SS, Lynch DT, Jitawatanarat P, Burrington CM, Dauchy EM, Blask DE, Greene MW. Light at night activates IGF-1R/PDK1 signaling and accelerates tumor growth in human breast cancer xenografts. Cancer Res 2011; 71:2622-31. [PMID: 21310824 DOI: 10.1158/0008-5472.can-10-3837] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Regulation of diurnal and circadian rhythms and cell proliferation are coupled in all mammals, including humans. However, the molecular mechanisms by which diurnal and circadian rhythms regulate cell proliferation are relatively poorly understood. In this study, we report that tumor growth in nude rats bearing human steroid receptor-negative MCF-7 breast tumors can be significantly accelerated by exposing the rats to light at night (LAN). Under normal conditions of an alternating light/dark cycle, proliferating cell nuclear antigen (PCNA) levels in tumors were maximal in the early light phase but remained at very low levels throughout the daily 24-hour cycle period monitored. Surprisingly, PCNA was expressed in tumors continually at a high level throughout the entire 24-hour period in LAN-exposed nude rats. Daily fluctuations of Akt and mitogen activated protein kinase activation in tumors were also disrupted by LAN. These fluctuations did not track with PCNA changes, but we found that activation of the Akt stimulatory kinase phosphoinositide-dependent protein kinase 1 (PDK1) directly correlated with PCNA levels. Expression of insulin-like growth factor 1 receptor (IGF-1R), an upstream signaling molecule for PDK1, also correlated with fluctuations of PDK1/PCNA in the LAN group. In addition, circulating IGF-1 concentrations were elevated in LAN-exposed tumor-bearing nude rats. Finally, RNAi-mediated knockdown of PDK1 led to a reduction in PCNA expression and cell proliferation in vitro and tumor growth in vivo, indicating that PDK1 regulates breast cancer growth in a manner correlated with PCNA expression. Taken together, our findings demonstrate that LAN exposure can accelerate tumor growth in vivo, in part through continuous activation of IGF-1R/PDK1 signaling.
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Affiliation(s)
- Jinghai Wu
- Bassett Research Institute and Department of Internal Medicine, Bassett Healthcare Network, Cooperstown, New York, USA
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