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Vogt PK, Hart JR, Yang S, Zhou Q, Yang D, Wang MW. Structural and mechanistic insights provided by single particle cryo-EM analysis of phosphoinositide 3-kinase (PI3Kα). Biochim Biophys Acta Rev Cancer 2023; 1878:188947. [PMID: 37394020 PMCID: PMC10530483 DOI: 10.1016/j.bbcan.2023.188947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023]
Abstract
Recent cryo-electron microscopic (cryo-EM) investigations have succeeded in the analysis of various structural conformations and functional states of PI3Kα, a dimer consisting of the catalytic subunit p110α and the regulatory subunit p85α of class IA of phosphoinositide 3-kinase. High resolution structures have been obtained of the unliganded and of BYL-719-bound PI3Kα. The latter provides information on excessively flexible domains of p85α that are then further analyzed with nanobodies and CXMS (chemical cross-linking, digestion and mass spectrometry). Analysis of p110α helical and kinase domain mutations reveals mutant-specific features that can be linked to the gain of function in enzymatic and signaling activities.
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Affiliation(s)
- Peter K Vogt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, United States of America.
| | - Jonathan R Hart
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, United States of America
| | - Su Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, United States of America
| | - Qingtong Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Dehua Yang
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China; Research Center for Deepsea Bioresources, Sanya 572025, China; Department of Chemistry, School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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2
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Cryo-EM structures of cancer-specific helical and kinase domain mutations of PI3Kα. Proc Natl Acad Sci U S A 2022; 119:e2215621119. [PMID: 36343266 PMCID: PMC9674216 DOI: 10.1073/pnas.2215621119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that perform multiple and important cellular functions. The protein investigated here belongs to class IA of the PI3Ks; it is a dimer consisting of a catalytic subunit, p110α, and a regulatory subunit, p85α, and is referred to as PI3Kα. The catalytic subunit p110α is frequently mutated in cancer. The mutations induce a gain of function and constitute a driving force in cancer development. About 80% of these mutations lead to single-amino-acid substitutions in one of three sites of p110α: two in the helical domain of the protein (E542K and E545K) and one at the C-terminus of the kinase domain (H1047R). Here, we report the cryo-electron microscopy structures of these mutants in complex with the p110α-specific inhibitor BYL-719. The H1047R mutant rotates its sidechain to a new position and weakens the kα11 activation loop interaction, thereby reducing the inhibitory effect of p85α on p110α. E542K and E545K completely abolish the tight interaction between the helical domain of p110α and the N-terminal SH2 domain of p85α and lead to the disruption of all p85α binding and a dramatic increase in flexibility of the adaptor-binding domain (ABD) in p110α. Yet, the dimerization of PI3Kα is preserved through the ABD-p85α interaction. The local and global structural features induced by these mutations provide molecular insights into the activation of PI3Kα, deepen our understanding of the oncogenic mechanism of this important signaling molecule, and may facilitate the development of mutant-specific inhibitors.
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Nanobodies and chemical cross-links advance the structural and functional analysis of PI3Kα. Proc Natl Acad Sci U S A 2022; 119:e2210769119. [PMID: 36095215 PMCID: PMC9499577 DOI: 10.1073/pnas.2210769119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nanobodies and chemical cross-linking were used to gain information on the identity and positions of flexible domains of PI3Kα. The application of chemical cross-linking mass spectrometry (CXMS) facilitated the identification of the p85 domains BH, cSH2, and SH3 as well as their docking positions on the PI3Kα catalytic core. Binding of individual nanobodies to PI3Kα induced activation or inhibition of enzyme activity and caused conformational changes that could be correlated with enzyme function. Binding of nanobody Nb3-126 to the BH domain of p85α substantially improved resolution for parts of the PI3Kα complex, and binding of nanobody Nb3-159 induced a conformation of PI3Kα that is distinct from known PI3Kα structures. The analysis of CXMS data also provided mechanistic insights into the molecular underpinning of the flexibility of PI3Kα.
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Zhou J, Imani S, Shasaltaneh MD, Liu S, Lu T, Fu J. PIK3CA hotspot mutations p. H1047R and p. H1047L sensitize breast cancer cells to thymoquinone treatment by regulating the PI3K/Akt1 pathway. Mol Biol Rep 2021; 49:1799-1816. [PMID: 34816327 DOI: 10.1007/s11033-021-06990-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/18/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND Nigella sativa (N. sativa) exhibits anti-inflammatory, antioxidant, antidiabetic, antimetastatic and antinociceptive effects and has been used to treat dozens of diseases. Thymoquinone (TQ) is an important and active component isolated from N. sativa seeds. Inhibition of cancer-associated activating PIK3CA mutations is a new prospective targeted therapy in personalized metastatic breast cancer (MBC). TQ is reported to be an effective inhibitor of the PI3K/Akt1 pathway in MBC. This study aimed to evaluate the in vitro antitumor effect of TQ in the context of two PIK3CA hotspot mutations, p. H1047R and p. H1047L. METHODS AND RESULTS Molecular dynamics, free energy landscapes and principal component analyses were also used to survey the mechanistic effects of the p. H1047R and p. H1047L mutations on the PI3K/Akt1 pathway. Our findings clearly confirmed that the p. H1047R and p. H1047L mutants could reduce the inhibitory effect of ΔNp63α on the kinase domain of PIK3CA, resulting in increased activity of PI3K downstream signals. Structurally, the partial disruption of the interaction between the ΔNp63α DNA binding domain and the PIK3CA kinase domain at residues 114-359 and 797-1068 destabilizes the conformation of the activation loop and modifies the PIK3CA/ΔNp63α complex. Alongside these structural changes, we found that TQ treatment resulted in high PI3K/Akt1 pathway inhibition in p. H1047R and p. H1047L-expressing cells versus wild-type cells. CONCLUSIONS These two PIK3CA hotspot mutations therefore not only contribute to tumor progression in patients with MBC but may also serve as targets for the development of novel small molecule therapeutic strategies.
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Affiliation(s)
- Ju Zhou
- Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Saber Imani
- Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | | | - Shuguang Liu
- Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Tao Lu
- Research Center for Science, Chengdu Medical College, Chengdu, Sichuan, China
| | - Junjiang Fu
- Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, 646000, Sichuan, China.
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Dong S, Liu Q, Xu Z, Wang H. An Unusual Case of Metastatic Basal Cell Carcinoma of the Prostate: A Case Report and Literature Review. Front Oncol 2020; 10:859. [PMID: 32537438 PMCID: PMC7267053 DOI: 10.3389/fonc.2020.00859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 04/30/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Primary basal cell carcinoma (BCC) is a rare prostate cancer. Currently, a standard treatment regime for BCC of the prostate is lacking and most patients have a poor prognosis. We reported on a patient with BCC of the prostate whose cancer metastasized after undergoing a radical prostatectomy and whose prognosis improved after treatment with etoposide. Case Presentation: A 62-year-old male with a history of seminoma was admitted complaining of intermittent gross hematuria for 1 month. Following a prostate biopsy, the patient was diagnosed with BCC of the prostate and received radical prostatectomy and radiotherapy. Initially, the patient's symptoms improved; however, 2 years later, a chest computed tomography (CT) scan revealed lung nodules. The patient did not exhibit any symptoms of BCC of the prostate; however, pathological examination and immunohistochemical staining of the nodules confirmed metastatic BCC of the prostate. Chemotherapy with docetaxel and cisplatin was well-tolerated but did not slow disease progression. Next-generation sequencing revealed mutations in the ataxia telangiectasia-mutated (ATM), SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily b-member 1 (SMARCB1), and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) genes. The patient did not receive targeted therapy owing to financial limitations and instead, etoposide was administered. A 9-month follow-up chest CT scan showed an 80% reduction in existing lung nodules and no new nodules had developed. Conclusion: Our patient, diagnosed with recurrent prostate BCC after receiving a radical prostatectomy, responded to treatment with etoposide. Radical prostatectomy and radiotherapy should remain first-line therapy; however, etoposide may be an alternative second-line therapy when other options are not available. Consensus regarding treatment plans, and the molecular mechanisms behind prostate BBC, must be elucidated.
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Affiliation(s)
- Shiqiang Dong
- Department of Oncology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin, China
| | - Qing Liu
- Department of Oncology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin, China
| | - Zihan Xu
- Department of Oncology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin, China
| | - Haitao Wang
- Department of Oncology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin, China
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Kim H, Shin KK, Kim HG, Jo M, Kim JK, Lee JS, Choung ES, Li WY, Lee SW, Kim KH, Yoo BC, Cho JY. Src/NF-κB-Targeted Anti-Inflammatory Effects of Potentilla glabra var. Mandshurica (Maxim.) Hand.-Mazz. Ethanol Extract. Biomolecules 2020; 10:biom10040648. [PMID: 32331432 PMCID: PMC7225925 DOI: 10.3390/biom10040648] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Inflammation is a complex protective response of body tissues to harmful stimuli. Acute inflammation can progress to chronic inflammation, which can lead to severe disease. Therefore, this research focuses on the development of anti-inflammatory drugs, and natural extracts have been explored as potential agents. No study has yet examined the inflammation-associated pharmacological activity of Potentilla glabra Var. mandshurica (Maxim.) Hand.-Mazz ethanol extract (Pg-EE). To examine the mechanisms by which Pg-EE exerts anti-inflammatory effects, we studied its activities in lipopolysaccharide (LPS)-treated murine macrophage RAW264.7 cells and an HCl/EtOH-induced gastritis model. LPS-triggered nitric oxide (NO) release and mRNA levels of inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) in RAW264.7 cells were suppressed by Pg-EE in a dose-dependent manner. Using a luciferase assay and western blot assay, we found that the NF-κB pathway was inhibited by Pg-EE, particularly by the decreased level of phosphorylated proteins of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) subunits (p65 and p50), inhibitor of kappa B alpha (IκBα), p85, and Src. Using an overexpression strategy, cellular thermal shift assay, and immunoprecipitation analysis, we determined that the anti-inflammatory effect of Pg-EE was mediated by the inhibition of Src. Pg-EE further showed anti-inflammatory effects in vivo in the HCl/EtOH-induced gastritis mouse model. In conclusion, Pg-EE exerts anti-inflammatory activities by targeting Src in the NF-κB pathway, and these results suggest that Pg-EE could be used as an anti-inflammatory herbal medicine.
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Affiliation(s)
- Haeyeop Kim
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
| | - Kon Kuk Shin
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
| | - Han Gyung Kim
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
- Research Institute of Biomolecule Control and Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon 16419, Korea
| | - Minkyeong Jo
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
| | - Jin Kyeong Kim
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
| | - Jong Sub Lee
- DanjoungBio Co., Ltd., Wonju 26303, Korea; (J.S.L.); (E.S.C.)
| | - Eui Su Choung
- DanjoungBio Co., Ltd., Wonju 26303, Korea; (J.S.L.); (E.S.C.)
| | - Wan Yi Li
- Institute of Medicinal Plants, Yunnan Academy of Agricultural Sciences, Kunming 650224, China;
| | - Sang Woo Lee
- International Biological Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea;
| | - Kyung-Hee Kim
- Biomarker Branch, Research Institute, National Cancer Center, Goyang 10408, Korea;
| | - Byong Chul Yoo
- Biomarker Branch, Research Institute, National Cancer Center, Goyang 10408, Korea;
- Correspondence: (B.C.Y.); (J.Y.C.); Tel.: +82-31-920-2342 (B.C.Y.); +82-31-290-7876 (J.Y.C.)
| | - Jae Youl Cho
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (K.K.S.); (H.G.K.); (M.J.); (J.K.K.)
- Research Institute of Biomolecule Control and Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon 16419, Korea
- Correspondence: (B.C.Y.); (J.Y.C.); Tel.: +82-31-920-2342 (B.C.Y.); +82-31-290-7876 (J.Y.C.)
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7
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Abstract
An unresolved question critical for understanding cancer is how recurring somatic mutations are retained and how selective pressures drive retention. Increased intracellular pH (pHi) is common to most cancers and is an early event in cancer development. Recent work shows that recurrent somatic mutations can confer an adaptive gain in pH sensing to mutant proteins, enhancing tumorigenic phenotypes specifically at the increased pHi of cancer. Newly identified amino acid mutation signatures in cancer suggest charge-changing mutations define and shape the mutational landscape of cancer. Taken together, these results support a new perspective on the functional significance of somatic mutations in cancer. In this review, we explore existing data and new directions for better understanding how changes in dynamic pH sensing by somatic mutation might be conferring a fitness advantage to the high pH of cancer.
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Allosteric Activation of PI3Kα Results in Dynamic Access to Catalytically Competent Conformations. Structure 2020; 28:465-474.e5. [PMID: 32049032 DOI: 10.1016/j.str.2020.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/21/2019] [Accepted: 01/16/2020] [Indexed: 11/30/2022]
Abstract
Class I phosphoinositide-3-kinases (PI3Ks) phosphorylate PIP2 at its 3' inositol position to generate PIP3, a second messenger that influences signaling cascades regulating cellular growth, survival, and proliferation. Previous studies have suggested that PI3Kα activation involves dislodging the p85α nSH2 domain from the p110α catalytic subunit by binding activated receptor tyrosine kinases. We carried out molecular dynamics simulations to determine, mechanistically and structurally, how PI3Kα conformations are influenced by physiological effectors and the nSH2 domain. We demonstrate that changes in protein dynamics mediated by allosteric regulation significantly increase the population of catalytically competent states without changing the enzyme ground-state structure. Furthermore, we demonstrate that modulation of active-site residue interactions with enzyme substrates can reciprocally influence nSH2 domain dynamics. Together, these results suggest that dynamic allostery plays a role in populating the catalytically competent conformation of PI3Kα, and provide a key platform for the design of novel chemotherapeutic PI3Kα inhibitors.
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9
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Nussinov R, Tsai C, Jang H. Autoinhibition can identify rare driver mutations and advise pharmacology. FASEB J 2019; 34:16-29. [DOI: 10.1096/fj.201901341r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/18/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section Basic Science Program Frederick National Laboratory for Cancer Research Frederick MD USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Chung‐Jung Tsai
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Hyunbum Jang
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
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10
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Dynamic Protein Allosteric Regulation and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1163:25-43. [DOI: 10.1007/978-981-13-8719-7_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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11
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Papa A, Pandolfi PP. The PTEN⁻PI3K Axis in Cancer. Biomolecules 2019; 9:biom9040153. [PMID: 30999672 PMCID: PMC6523724 DOI: 10.3390/biom9040153] [Citation(s) in RCA: 158] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 12/25/2022] Open
Abstract
The PI3K-AKT-mTOR signal transduction pathway regulates a variety of biological processes including cell growth, cell cycle progression and proliferation, cellular metabolism, and cytoskeleton reorganization. Fine-tuning of the phosphatidylinositol 3-kinase (PI3K) pathway signaling output is essential for the maintenance of tissue homeostasis and uncontrolled activation of this cascade leads to a number of human pathologies including cancer. Inactivation of the tumor suppressor phosphatase and tensin homologue deleted on Chromosome 10 (PTEN) and/or activating mutations in the proto-typical lipid kinase PI3K have emerged as some of the most frequent events associated with human cancer and as a result the PI3K pathway has become a highly sought-after target for cancer therapies. In this review we summarize the essential role of the PTEN-PI3K axis in controlling cellular behaviors by modulating activation of key proto-oncogenic molecular nodes and functional targets. Further, we highlight important functional redundancies and peculiarities of these two critical enzymes that over the last few decades have become a central part of the cancer research field and have instructed hundreds of pre-clinical and clinical trials to better cancer treatments.
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Affiliation(s)
- Antonella Papa
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia.
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School, Boston, MA 02215, USA.
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12
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Zhang M, Jang H, Nussinov R. The mechanism of PI3Kα activation at the atomic level. Chem Sci 2019; 10:3671-3680. [PMID: 30996962 PMCID: PMC6430085 DOI: 10.1039/c8sc04498h] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/19/2019] [Indexed: 12/19/2022] Open
Abstract
PI3K lipid kinases phosphorylate PIP2 to PIP3 in the PI3K/Akt/mTOR pathway to regulate cellular processes. They are frequently mutated in cancer. Here we determine the PI3Kα activation mechanism at the atomic level. Unlike protein kinases where the substrate abuts the ATP, crystal structures indicate that in PI3Kα, the distance between the γ phosphate of the ATP and the PIP2 lipid substrate is over 6 Å, much too far for the phosphoryl transfer, raising the question of how catalysis is executed. PI3Kα has two subunits, the catalytic p110α and the regulatory p85α. Our simulations show that release of the autoinhibition exerted by the nSH2 domain of the p85α triggers significant conformational change in p110α, leading to the exposure of the kinase domain for membrane interaction. Structural rearrangement in the C-lobe of the kinase domain reduces the distance between the ATP γ-phosphate and the substrate, offering an explanation as to how phosphoryl transfer is executed. An alternative mechanism may involve ATP relocation. This mechanism not only explains how oncogenic mutations promote PI3Kα activation by facilitating nSH2 release, or nSH2-release-induced, allosteric motions; it also offers an innovative, PI3K isoform-specific drug discovery principle. Rather than competing with nanomolar range ATP in the ATP-binding pocket and contending with ATP pocket conservation and massive binding targets, this mechanism suggests blocking the PI3Kα sequence-specific cavity between the ATP-binding pocket and the substrate binding site. Targeting isoform-specific residues in the cavity may prevent PIP2 phosphorylation.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section , Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , MD 21702 , USA .
| | - Hyunbum Jang
- Computational Structural Biology Section , Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , MD 21702 , USA .
| | - Ruth Nussinov
- Computational Structural Biology Section , Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , MD 21702 , USA . .,Department of Human Molecular Genetics and Biochemistry , Sackler School of Medicine , Tel Aviv University , Tel Aviv 69978 , Israel
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13
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Fricke SL, Payne SN, Favreau PF, Kratz JD, Pasch CA, Foley TM, Yueh AE, Van De Hey DR, Depke MG, Korkos DP, Sha GC, DeStefanis RA, Clipson L, Burkard ME, Lemmon KK, Parsons BM, Kenny PA, Matkowskyj KA, Newton MA, Skala MC, Deming DA. MTORC1/2 Inhibition as a Therapeutic Strategy for PIK3CA Mutant Cancers. Mol Cancer Ther 2019; 18:346-355. [PMID: 30425131 PMCID: PMC6363831 DOI: 10.1158/1535-7163.mct-18-0510] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/20/2018] [Accepted: 11/08/2018] [Indexed: 12/30/2022]
Abstract
PIK3CA mutations are common in clinical molecular profiling, yet an effective means to target these cancers has yet to be developed. MTORC1 inhibitors are often used off-label for patients with PIK3CA mutant cancers with only limited data to support this approach. Here we describe a cohort of patients treated with cancers possessing mutations activating the PI3K signaling cascade with minimal benefit to treatment with the MTORC1 inhibitor everolimus. Previously, we demonstrated that dual PI3K/mTOR inhibition could decrease proliferation, induce differentiation, and result in a treatment response in APC and PIK3CA mutant colorectal cancer. However, reactivation of AKT was identified, indicating that the majority of the benefit may be secondary to MTORC1/2 inhibition. TAK-228, an MTORC1/2 inhibitor, was compared with dual PI3K/mTOR inhibition using BEZ235 in murine colorectal cancer spheroids. A reduction in spheroid size was observed with TAK-228 and BEZ235 (-13% and -14%, respectively) compared with an increase of >200% in control (P < 0.001). These spheroids were resistant to MTORC1 inhibition. In transgenic mice possessing Pik3ca and Apc mutations, BEZ235 and TAK-228 resulted in a median reduction in colon tumor size of 19% and 20%, respectively, with control tumors having a median increase of 18% (P = 0.02 and 0.004, respectively). This response correlated with a decrease in the phosphorylation of 4EBP1 and RPS6. MTORC1/2 inhibition is sufficient to overcome resistance to everolimus and induce a treatment response in PIK3CA mutant colorectal cancers and deserves investigation in clinical trials and in future combination regimens.
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Affiliation(s)
- Stephanie L Fricke
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Susan N Payne
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
| | | | - Jeremy D Kratz
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Cheri A Pasch
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
| | - Tyler M Foley
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alexander E Yueh
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Dana R Van De Hey
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Mitchell G Depke
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Demetra P Korkos
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Gioia Chengcheng Sha
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Rebecca A DeStefanis
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Linda Clipson
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Mark E Burkard
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kayla K Lemmon
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
| | | | | | - Kristina A Matkowskyj
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin
- William S Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Michael A Newton
- Department of Statistics and Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Melissa C Skala
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
- Morgridge Institute for Research, Madison, Wisconsin
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin
| | - Dustin A Deming
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
- University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, Wisconsin
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin
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Coronas-Serna JM, Fernández-Acero T, Molina M, Cid VJ. A humanized yeast-based toolkit for monitoring phosphatidylinositol 3-kinase activity at both single cell and population levels. ACTA ACUST UNITED AC 2018; 5:545-554. [PMID: 30533419 PMCID: PMC6282018 DOI: 10.15698/mic2018.12.660] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Phosphatidylinositol 3-kinase (PI3K) is a key regulator of phosphoinositide-dependent signaling in mammalian cells and its dysfunction is related to multiple syndromes, including cancer. By heterologous expression in Saccharomyces cerevisiae, we have developed a humanized yeast system as a tool for functional studies on higher eukaryotic PI3K. Here we restrict PI3K activity in yeast to specific plasma membrane (PM) microdomains by fusing the p110α PI3K catalytic subunit to either a septin or an eisosome component. We engineered a Dual Reporter for PI3K (DRAPIK), useful to monitor activity on cellular membranes in vivo at a single-cell level, by simultaneous PM staining of the enzyme substrate (PtdIns4,5P2) with GFP and its product (PtdIns3,4,5P3) with mCherry. We also developed a sensitive FLUorescence by PI3K Inhibition (FLUPI) assay based on a GFP transcriptional reporter that is turned off by PI3K activity. This reporter system proved useful to monitor PI3K inhibition in vivo by active compounds. Such novel tools were used to study the performance of yeast PM microdomain-directed PI3K. Our results show that tethering heterologous PI3K to discrete PM domains potentiates its activity on PtdIns4,5P2 but different locations display distinct effects on yeast growth and endocytosis.
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Affiliation(s)
- Julia María Coronas-Serna
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
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15
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Lachkar B, Minaguchi T, Akiyama A, Liu S, Zhang S, Xu C, Shikama A, Tasaka N, Sakurai M, Nakao S, Ochi H, Yoshikawa H, Satoh T. Prognostic significance of PIK3CA mutation in stage IIB to IVA cervical cancers treated by concurrent chemoradiotherapy with weekly cisplatin. Medicine (Baltimore) 2018; 97:e11392. [PMID: 30075505 PMCID: PMC6081058 DOI: 10.1097/md.0000000000011392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The standard treatment for locally advanced cervical cancer is cisplatin-based concurrent chemoradiotherapy (CCRT). Although the activated PI3-kinase/Akt pathway is known to be involved in both cisplatin-resistance and radioresistance, to date, only a few studies have reported significant associations between PIK3CA gene mutational status and outcome by CCRT in the disease. The aim of this study was to clarify the prognostic significance of PIK3CA mutational status in cervical cancers treated by CCRT.We analyzed PIK3CA mutation in 59 patients with stage IIB to IVA cervical carcinomas primarily treated by CCRT with weekly cisplatin using formalin-fixed paraffin-embedded biopsy specimens before treatment. Fifty-seven of 59 patients (97%) had locally advanced cancers with stage IIIA to IVA. Clinicopathologic data and patient survival were retrospectively compared according to PIK3CA mutational status.PIK3CA mutation was found in 7 of 59 patients (12%). No significant differences in clinicopathologic characteristics were observed according to PIK3CA mutational status. Patients with wild-type PIK3CA showed significantly improved cancer-specific survival as compared with mutated patients (P = .044). Subsequent survival analyses revealed that PIK3CA mutation was a significant prognostic factor for poor overall survival [multivariate adjusted hazard ratio (HR), 3.9; 95% confidence interval (95% CI), 1.3-11.8; P = .017] and cancer-specific survival (multivariate adjusted HR, 3.6; 95% CI, 1.2-11.0; P = .024).Together with previous published findings, the current study further supports the clinical significance of PIK3CA mutation in cervical cancer. Our observations suggest that molecular inhibitors targeting the PI3-kinase/Akt pathway may improve the outcome by CCRT in cervical cancers harboring PIK3CA mutation, providing significant implications for novel treatment strategy based on precision medicine in the disease.
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Affiliation(s)
- Bouchra Lachkar
- Doctoral Program in Obstetrics and Gynecology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba
| | - Takeo Minaguchi
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Azusa Akiyama
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Shuling Liu
- Doctoral Program in Obstetrics and Gynecology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba
| | - Shuang Zhang
- Doctoral Program in Obstetrics and Gynecology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba
| | - Chenyang Xu
- Doctoral Program in Obstetrics and Gynecology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba
| | - Ayumi Shikama
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Nobutaka Tasaka
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Manabu Sakurai
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Sari Nakao
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Hiroyuki Ochi
- Department of Obstetrics and Gynecology, Faculty of Medicine
| | - Hiroyuki Yoshikawa
- Department of Obstetrics and Gynecology, Faculty of Medicine
- Ibaraki Prefectural Central Hospital, Ibaraki, Japan
| | - Toyomi Satoh
- Department of Obstetrics and Gynecology, Faculty of Medicine
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16
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Ignacio RMC, Gibbs CR, Lee ES, Son DS. The TGFα-EGFR-Akt signaling axis plays a role in enhancing proinflammatory chemokines in triple-negative breast cancer cells. Oncotarget 2018; 9:29286-29303. [PMID: 30034618 PMCID: PMC6047672 DOI: 10.18632/oncotarget.25389] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/28/2018] [Indexed: 12/30/2022] Open
Abstract
Triple-negative breast cancer (TNBC) is aggressive and typically has a poor prognosis. Chemokines have chemoattractant potential for cancer metastasis. Here, we investigated the chemokine signatures in BC subtypes and the underlying mechanisms that enhance proinflammatory chemokines in TNBC. Analysis from microarray dataset revealed that basal-like BC subtype including TNBC expressed dominantly proinflammatory chemokines, such as CXCL1 and 8, compared to non-TNBC. Chemokine PCR array confirmed the dominant chemokines in TNBC cells. To identify a driving factor for proinflammatory chemokines in TNBC cells, we determined the expression and signaling profiles of epidermal growth factor receptor (EGFR) family members. TNBC cells expressed higher levels of EGFR and phosphorylated Akt/Erk than non-TNBC cells. In addition, EGF further enhanced the proinflammatory chemokines in TNBC cells, including CXCL2. Knockdown of Akt reduced the CXCL2 promoter activity, while overexpression of Akt enhanced it. MK2206, an Akt inhibitor, reduced the CXCL2 promoter activity, while inhibition and knockdown of Erk did not reduce its activity. We found that transforming growth factor alpha (TGFα) could serve as a main ligand for EGFR to drive EGFR-mediated Akt activation in TNBC cells. MK2206 decreased TGFα promoter activity, while overexpression of Akt increased it. MK2206 also reduced TGFα release from TNBC cells. Moreover, MK2206 downregulated CXCL2 mRNA expression, while TGFα upregulated it. Taken together, the TGFα-EGFR-Akt signaling axis can play a role in enhancing proinflammatory chemokine expression in TNBC, subsequently contributing to the inflammatory burden that ultimately lead to cancer progression and a higher mortality rate among TNBC patients.
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Affiliation(s)
- Rosa Mistica C Ignacio
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208 USA
| | - Carla R Gibbs
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208 USA
| | - Eun-Sook Lee
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL 32301 USA
| | - Deok-Soo Son
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208 USA
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17
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Phosphorylation of PI3K regulatory subunit p85 contributes to resistance against PI3K inhibitors in radioresistant head and neck cancer. Oral Oncol 2018; 78:56-63. [PMID: 29496059 DOI: 10.1016/j.oraloncology.2018.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/09/2018] [Accepted: 01/18/2018] [Indexed: 12/27/2022]
Abstract
OBJECTIVES PI3K/Akt/mTOR pathway is commonly activated in most cancers and is correlated with resistance to anticancer therapies such as radiotherapy. Therefore, PI3K is an attractive target for treating PI3K-associated cancers. MATERIAL AND METHODS We investigated the basal expression and the expression after treatment of PI3K inhibitor or Src inhibitor of PI3K/Akt pathway-related proteins in AMC-HN3, AMC-HN3R, HN30 and HN31 cells by performing immunoblotting analysis. The sensitivity to PI3K inhibitors or Src inhibitor was analyzed by MTT assay and clonogenic assay. To determine the antitumoral activity of combination treatment with PI3K inhibitor and Src inhibitor, we used using xenograft mouse model. RESULTS We found that PI3K regulatory subunit p85 was predominantly phosphorylated in radioresistant head and neck cancer cell line (HN31), which showed resistance to PI3K inhibitors. Next, we investigated mechanism through which PI3K p85 phosphorylation modulated response to PI3K inhibitors. Of note, constitutive activation of Src was found in HN31 cells and upon PI3K inhibitor treatment, restoration of p-Src was occurred. Src inhibitor improved the efficacy of PI3K inhibitor treatment and suppressed the reactivation of both Src and PI3K p85 in HN31 cells. Furthermore, downregulation of PI3K p85 expression by using a specific siRNA suppressed Src phosphorylation. CONCLUSIONS Together, our results imply the novel role of the PI3K regulatory subunit p85 in the development of resistance to PI3K inhibitors and suggest the presence of a regulatory loop between PI3K p85 and Src in radioresistant head and neck cancers with constitutively active PI3K/Akt pathway.
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18
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Jovanović M, Nikolić K, Gagić Ž, Agbaba D. Molecular modeling and analysis of the 3D pharmacophore structure of the selective PI3K-α inhibitors as antitumor agents. ARHIV ZA FARMACIJU 2018. [DOI: 10.5937/arhfarm1804860j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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19
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Functional analysis of Cullin 3 E3 ligases in tumorigenesis. Biochim Biophys Acta Rev Cancer 2017; 1869:11-28. [PMID: 29128526 DOI: 10.1016/j.bbcan.2017.11.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 12/14/2022]
Abstract
Cullin 3-RING ligases (CRL3) play pivotal roles in the regulation of various physiological and pathological processes, including neoplastic events. The substrate adaptors of CRL3 typically contain a BTB domain that mediates the interaction between Cullin 3 and target substrates to promote their ubiquitination and subsequent degradation. The biological implications of CRL3 adaptor proteins have been well described where they have been found to play a role as either an oncogene, tumor suppressor, or can mediate either of these effects in a context-dependent manner. Among the extensively studied CRL3-based E3 ligases, the role of the adaptor protein SPOP (speckle type BTB/POZ protein) in tumorigenesis appears to be tissue or cellular context dependent. Specifically, SPOP acts as a tumor suppressor via destabilizing downstream oncoproteins in many malignancies, especially in prostate cancer. However, SPOP has largely an oncogenic role in kidney cancer. Keap1, another well-characterized CRL3 adaptor protein, likely serves as a tumor suppressor within diverse malignancies, mainly due to its specific turnover of its downstream oncogenic substrate, NRF2 (nuclear factor erythroid 2-related factor 2). In accordance with the physiological role the various CRL3 adaptors exhibit, several pharmacological agents have been developed to disrupt its E3 ligase activity, therefore blocking its potential oncogenic activity to mitigate tumorigenesis.
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20
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Marini BL, Benitez LL, Zureick AH, Salloum R, Gauthier AC, Brown J, Wu YM, Robinson DR, Kumar C, Lonigro R, Vats P, Cao X, Kasaian K, Anderson B, Mullan B, Chandler B, Linzey JR, Camelo-Piragua SI, Venneti S, McKeever PE, McFadden KA, Lieberman AP, Brown N, Shao L, Leonard MAS, Junck L, McKean E, Maher CO, Garton HJL, Muraszko KM, Hervey-Jumper S, Mulcahy-Levy JM, Green A, Hoffman LM, Dorris K, Vitanza NA, Wang J, Schwartz J, Lulla R, Smiley NP, Bornhorst M, Haas-Kogan DA, Robertson PL, Chinnaiyan AM, Mody R, Koschmann C. Blood-brain barrier-adapted precision medicine therapy for pediatric brain tumors. Transl Res 2017; 188:27.e1-27.e14. [PMID: 28860053 PMCID: PMC5584679 DOI: 10.1016/j.trsl.2017.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/24/2017] [Accepted: 08/04/2017] [Indexed: 10/19/2022]
Abstract
Targeted chemotherapeutics provide a promising new treatment option in neuro-oncology. The ability of these compounds to penetrate the blood-brain barrier is crucial for their successful incorporation into patient care. "CNS Targeted Agent Prediction" (CNS-TAP) is a multi-institutional and multidisciplinary translational program established at the University of Michigan for evaluating the central nervous system (CNS) activity of targeted therapies in neuro-oncology. In this report, we present the methodology of CNS-TAP in a series of pediatric and adolescent patients with high-risk brain tumors, for which molecular profiling (academic and commercial) was sought and targeted agents were incorporated. Four of five of the patients had potential clinical benefit (partial response or stable disease greater than 6 months on therapy). We further describe the specific drug properties of each agent chosen and discuss characteristics relevant in their evaluation for therapeutic suitability. Finally, we summarize both tumor and drug characteristics that impact the ability to successfully incorporate targeted therapies into CNS malignancy management.
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Affiliation(s)
- Bernard L Marini
- Michigan Medicine, Department of Pharmacy Services, Ann Arbor, Mich
| | - Lydia L Benitez
- Michigan Medicine, Department of Pharmacy Services, Ann Arbor, Mich; University of Kentucky Healthcare, Department of Pharmacy, Lexington, Ky
| | | | - Ralph Salloum
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | | | - Julia Brown
- Michigan Medicine, Department of Pharmacy Services, Ann Arbor, Mich
| | - Yi-Mi Wu
- University of Michigan Medical School, Ann Arbor, Mich
| | | | - Chandan Kumar
- University of Michigan Medical School, Ann Arbor, Mich
| | | | - Pankaj Vats
- University of Michigan Medical School, Ann Arbor, Mich
| | - Xuhong Cao
- University of Michigan Medical School, Ann Arbor, Mich
| | | | | | | | | | | | | | | | | | | | | | - Noah Brown
- University of Michigan Medical School, Ann Arbor, Mich
| | - Lina Shao
- University of Michigan Medical School, Ann Arbor, Mich
| | | | - Larry Junck
- University of Michigan Medical School, Ann Arbor, Mich
| | - Erin McKean
- University of Michigan Medical School, Ann Arbor, Mich
| | | | | | | | | | | | - Adam Green
- University of Colorado Denver School of Medicine, Denver, Colo
| | | | - Katie Dorris
- University of Colorado Denver School of Medicine, Denver, Colo
| | | | - Joanne Wang
- Children's Hospital of Michigan, Detroit, Mich
| | | | - Rishi Lulla
- Anne and Robert H. Lurie Children's Hospital of Chicago, Chicago Ill
| | | | | | | | | | | | - Rajen Mody
- University of Michigan Medical School, Ann Arbor, Mich
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21
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Szpiech ZA, Strauli NB, White KA, Ruiz DG, Jacobson MP, Barber DL, Hernandez RD. Prominent features of the amino acid mutation landscape in cancer. PLoS One 2017; 12:e0183273. [PMID: 28837668 PMCID: PMC5570307 DOI: 10.1371/journal.pone.0183273] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/01/2017] [Indexed: 01/20/2023] Open
Abstract
Cancer can be viewed as a set of different diseases with distinctions based on tissue origin, driver mutations, and genetic signatures. Accordingly, each of these distinctions have been used to classify cancer subtypes and to reveal common features. Here, we present a different analysis of cancer based on amino acid mutation signatures. Non-negative Matrix Factorization and principal component analysis of 29 cancers revealed six amino acid mutation signatures, including four signatures that were dominated by either arginine to histidine (Arg>His) or glutamate to lysine (Glu>Lys) mutations. Sample-level analyses reveal that while some cancers are heterogeneous, others are largely dominated by one type of mutation. Using a non-overlapping set of samples from the COSMIC somatic mutation database, we validate five of six mutation signatures, including signatures with prominent arginine to histidine (Arg>His) or glutamate to lysine (Glu>Lys) mutations. This suggests that our classification of cancers based on amino acid mutation patterns may provide avenues of inquiry pertaining to specific protein mutations that may generate novel insights into cancer biology.
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Affiliation(s)
- Zachary A. Szpiech
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States of America
- * E-mail: (RDH); (ZAS)
| | - Nicolas B. Strauli
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States of America
- Biomedical Sciences Graduate Program, University of California, San Francisco, United States of America
| | - Katharine A. White
- Department of Cell and Tissue Biology, University of California, San Francisco, United States of America
| | - Diego Garrido Ruiz
- Department of Pharmaceutical Chemistry, University of California, San Francisco, United States of America
| | - Matthew P. Jacobson
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States of America
- Department of Pharmaceutical Chemistry, University of California, San Francisco, United States of America
| | - Diane L. Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, United States of America
| | - Ryan D. Hernandez
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States of America
- Quantitative Biosciences Institute, University of California, San Francisco, United States of America
- Institute for Human Genetics, University of California, San Francisco, United States of America
- * E-mail: (RDH); (ZAS)
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22
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Ito Y, Vogt PK, Hart JR. Domain analysis reveals striking functional differences between the regulatory subunits of phosphatidylinositol 3-kinase (PI3K), p85α and p85β. Oncotarget 2017; 8:55863-55876. [PMID: 28915558 PMCID: PMC5593529 DOI: 10.18632/oncotarget.19866] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 07/12/2017] [Indexed: 01/24/2023] Open
Abstract
Our understanding of isoform-specific activities of phosphatidylinositol 3-kinase (PI3K) is still rudimentary, and yet, deep knowledge of these non-redundant functions in the PI3K family is essential for effective and safe control of PI3K in disease. The two major isoforms of the regulatory subunits of PI3K are p85α and p85β, encoded by the genes PIK3R1 and PIK3R2, respectively. These isoforms show distinct functional differences that affect and control cellular PI3K activity and signaling [1–4]. In this study, we have further explored the differences between p85α and p85β by genetic truncations and substitutions. We have discovered unexpected activities of the mutant proteins that reflect regulatory functions of distinct p85 domains. These results can be summarized as follows: Deletion of the SH3 domain increases oncogenic and PI3K signaling activity. Deletion of the combined SH3-RhoGAP domains abolishes these activities. In p85β, deletion of the cSH2 domain reduces oncogenic and signaling activities. In p85α, such a deletion has an activating effect. The deletions of the combined cSH2 and iSH2 domains and also the deletion of the cSH2, iSH2 and nSH2 domains yield results that go in the same direction, generally activating in p85α and reducing activity in p85β. The contrasting functions of the cSH2 domains are verified by domain exchanges with the cSH2 domain of p85β exerting an activating effect and the cSH2 domain of p85α an inactivating effect, even in the heterologous isoform. In the cell systems studied, protein stability was not correlated with oncogenic and signaling activity. These observations significantly expand our knowledge of the isoform-specific activities of p85α and p85β and of the functional significance of specific domains for regulating the catalytic subunits of class IA PI3K.
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Affiliation(s)
- Yoshihiro Ito
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, San Diego, CA, USA
| | - Peter K Vogt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, San Diego, CA, USA
| | - Jonathan R Hart
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, San Diego, CA, USA
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23
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Insights into the pathological mechanisms of p85α mutations using a yeast-based phosphatidylinositol 3-kinase model. Biosci Rep 2017; 37:BSR20160258. [PMID: 28143957 PMCID: PMC5350601 DOI: 10.1042/bsr20160258] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 01/16/2017] [Accepted: 01/31/2017] [Indexed: 01/01/2023] Open
Abstract
In higher eukaryotes, cell proliferation is regulated by class I phosphatidylinositol 3-kinase (PI3K), which transduces stimuli received from neighboring receptors by local generation of PtdIns(3,4,5)P3 in cellular membranes. PI3K is a heterodimeric protein consisting of a regulatory and a catalytic subunit (p85 and p110 respectively). Heterologous expression of p110α in Saccharomyces cerevisiae leads to toxicity by conversion of essential PtdIns(4,5)P2 into futile PtdIns(3,4,5)P3, providing a humanized yeast model for functional studies on this pathway. Here, we report expression and functional characterization in yeast of all regulatory and catalytic human PI3K isoforms, and exploitation of the most suitable setting to functionally assay panels of tumor- and germ line-associated PI3K mutations, with indications to the limits of the system. The activity of p110α in yeast was not compromised by truncation of its N-terminal adaptor-binding domain (ABD) or inactivation of the Ras-binding domain (RBD). In contrast, a cluster of positively charged residues at the C2 domain was essential. Expression of a membrane-driven p65α oncogenic-truncated version of p85α, but not the full-length protein, led to enhanced activity of α, β, and δ p110 isoforms. Mutations impairing the inhibitory regulation exerted by the p85α iSH2 domain on the C2 domain of p110α yielded the latter non-responsive to negative regulation, thus reproducing this oncogenic mechanism in yeast. However, p85α germ line mutations associated with short stature, hyperextensibility of joints and/or inguinal hernia, ocular depression, Rieger anomaly, and teething delay (SHORT) syndrome did not increase PI3K activity in this model, supporting the idea that SHORT syndrome-associated p85α mutations operate through mechanisms different from the canonical disruption of inhibitory p85–p110 interactions typical of cancer.
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24
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Foley TM, Payne SN, Pasch CA, Yueh AE, Van De Hey DR, Korkos DP, Clipson L, Maher ME, Matkowskyj KA, Newton MA, Deming DA. Dual PI3K/mTOR Inhibition in Colorectal Cancers with APC and PIK3CA Mutations. Mol Cancer Res 2017; 15:317-327. [PMID: 28184015 PMCID: PMC5550373 DOI: 10.1158/1541-7786.mcr-16-0256] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/18/2016] [Accepted: 11/30/2016] [Indexed: 12/30/2022]
Abstract
Therapeutic targeting of the PI3K pathway is an active area of research in multiple cancer types, including breast and endometrial cancers. This pathway is commonly altered in cancer and plays an integral role in numerous vital cellular functions. Mutations in the PIK3CA gene, resulting in a constitutively active form of PI3K, often occur in colorectal cancer, though the population of patients who would benefit from targeting this pathway has yet to be identified. In human colorectal cancers, PIK3CA mutations most commonly occur concomitantly with loss of adenomatous polyposis coli (APC). Here, treatment strategies are investigated that target the PI3K pathway in colon cancers with mutations in APC and PIK3CA Colorectal cancer spheroids with Apc and Pik3ca mutations were generated and characterized confirming that these cultures represent the tumors from which they were derived. Pan and alpha isomer-specific PI3K inhibitors did not induce a significant treatment response, whereas the dual PI3K/mTOR inhibitors BEZ235 and LY3023414 induced a dramatic treatment response through decreased cellular proliferation and increased differentiation. The significant treatment responses were confirmed in mice with Apc and Pik3ca-mutant colon cancers as measured using endoscopy with a reduction in median lumen occlusion of 53% with BEZ235 and a 24% reduction with LY3023414 compared with an increase of 53% in controls (P < 0.001 and P = 0.03, respectively). This response was also confirmed with 18F-FDG microPET/CT imaging.Implications: Spheroid models and transgenic mice suggest that dual PI3K/mTOR inhibition is a potential treatment strategy for APC and PIK3CA-mutant colorectal cancers. Thus, further clinical studies of dual PI3K/mTOR inhibitors are warranted in colorectal cancers with these mutations. Mol Cancer Res; 15(3); 1-11. ©2016 AACR.
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Affiliation(s)
- Tyler M Foley
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Susan N Payne
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Cheri A Pasch
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Alex E Yueh
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Dana R Van De Hey
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Demetra P Korkos
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Linda Clipson
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Molly E Maher
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kristina A Matkowskyj
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin
- William S Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Michael A Newton
- Departments of Statistics and of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Dustin A Deming
- Division of Hematology and Oncology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin
- William S Middleton Memorial Veterans Hospital, Madison, Wisconsin
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25
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Multiscale mutation clustering algorithm identifies pan-cancer mutational clusters associated with pathway-level changes in gene expression. PLoS Comput Biol 2017; 13:e1005347. [PMID: 28170390 PMCID: PMC5321471 DOI: 10.1371/journal.pcbi.1005347] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 02/22/2017] [Accepted: 01/04/2017] [Indexed: 12/22/2022] Open
Abstract
Cancer researchers have long recognized that somatic mutations are not uniformly distributed within genes. However, most approaches for identifying cancer mutations focus on either the entire-gene or single amino-acid level. We have bridged these two methodologies with a multiscale mutation clustering algorithm that identifies variable length mutation clusters in cancer genes. We ran our algorithm on 539 genes using the combined mutation data in 23 cancer types from The Cancer Genome Atlas (TCGA) and identified 1295 mutation clusters. The resulting mutation clusters cover a wide range of scales and often overlap with many kinds of protein features including structured domains, phosphorylation sites, and known single nucleotide variants. We statistically associated these multiscale clusters with gene expression and drug response data to illuminate the functional and clinical consequences of mutations in our clusters. Interestingly, we find multiple clusters within individual genes that have differential functional associations: these include PTEN, FUBP1, and CDH1. This methodology has potential implications in identifying protein regions for drug targets, understanding the biological underpinnings of cancer, and personalizing cancer treatments. Toward this end, we have made the mutation clusters and the clustering algorithm available to the public. Clusters and pathway associations can be interactively browsed at m2c.systemsbiology.net. The multiscale mutation clustering algorithm is available at https://github.com/IlyaLab/M2C.
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Lang MJ, Strunk BS, Azad N, Petersen JL, Weisman LS. An intramolecular interaction within the lipid kinase Fab1 regulates cellular phosphatidylinositol 3,5-bisphosphate lipid levels. Mol Biol Cell 2017; 28:858-864. [PMID: 28148651 PMCID: PMC5385934 DOI: 10.1091/mbc.e16-06-0390] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 11/24/2022] Open
Abstract
There is an intramolecular interaction in the lipid kinase Fab1 in which the upstream CCR domain contacts the Fab1 kinase region. Selected dominant-active alleles disrupt this interaction and result in elevated PI(3,5)P2. These findings suggest a regulatory mechanism that contributes to dynamic control of cellular PI(3,5)P2 synthesis. Phosphorylated phosphoinositide lipids (PPIs) are low-abundance signaling molecules that control signal transduction pathways and are necessary for cellular homeostasis. The PPI phosphatidylinositol (3,5)-bisphosphate (PI(3,5)P2) is essential in multiple organ systems. PI(3,5)P2 is generated from PI3P by the conserved lipid kinase Fab1/PIKfyve. Defects in the dynamic regulation of PI(3,5)P2 are linked to human diseases. However, few mechanisms that regulate PI(3,5)P2 have been identified. Here we report an intramolecular interaction between the yeast Fab1 kinase region and an upstream conserved cysteine-rich (CCR) domain. We identify mutations in the kinase domain that lead to elevated levels of PI(3,5)P2 and impair the interaction between the kinase and CCR domain. We also identify mutations in the CCR domain that lead to elevated levels of PI(3,5)P2. Together these findings reveal a regulatory mechanism that involves the CCR domain of Fab1 and contributes to dynamic control of cellular PI(3,5)P2 synthesis.
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Affiliation(s)
- Michael J Lang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Bethany S Strunk
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Nadia Azad
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Jason L Petersen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 .,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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Kalsi N, Gopalakrishnan C, Rajendran V, Purohit R. Biophysical aspect of phosphatidylinositol 3-kinase and role of oncogenic mutants (E542K & E545K). J Biomol Struct Dyn 2016; 34:2711-2721. [DOI: 10.1080/07391102.2015.1127774] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Sung NY, Kim MY, Cho JY. Scutellarein Reduces Inflammatory Responses by Inhibiting Src Kinase Activity. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:441-9. [PMID: 26330757 PMCID: PMC4553404 DOI: 10.4196/kjpp.2015.19.5.441] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 11/15/2022]
Abstract
Flavonoids are plant pigments that have been demonstrated to exert various pharmacological effects including anti-cancer, anti-diabetic, anti-atherosclerotic, anti-bacterial, and anti-inflammatory activities. However, the molecular mechanisms in terms of exact target proteins of flavonoids are not fully elucidated yet. In this study, we aimed to evaluate the anti-inflammatory mechanism of scutellarein (SCT), a flavonoid isolated from Erigeron breviscapus, Clerodendrum phlomidis and Oroxylum indicum Vent that have been traditionally used to treat various inflammatory diseases in China and Brazil. For this purpose, a nitric oxide (NO) assay, polymerase chain reaction (PCR), nuclear fractionation, immunoblot analysis, a kinase assay, and an overexpression strategy were employed. Scutellarein significantly inhibited NO production in a dose-dependent manner and reduced the mRNA expression levels of inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-activated RAW264.7 cells. In addition, SCT also dampened nuclear factor (NF)-κB-driven expression of a luciferase reporter gene upon transfection of a TIR-domain-containing adapter-inducing interferon-β (TRIF) construct into Human embryonic kidney 293 (HEK 293) cells; similarly, NF-κ B nuclear translocation was inhibited by SCT. Moreover, the phosphorylation levels of various upstream signaling enzymes involved in NF-κB activation were decreased by SCT treatment in LPS-treated RAW264.7 cells. Finally, SCT strongly inhibited Src kinase activity and also inhibited the autophosphorylation of overexpressed Src. Therefore, our data suggest that SCT can block the inflammatory response by directly inhibiting Src kinase activity linked to NF-κB activation.
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Affiliation(s)
- Nak Yoon Sung
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Korea
| | - Mi-Yeon Kim
- School of Systems Biological Science, Soongsil University, Seoul 156-743, Korea
| | - Jae Youl Cho
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Korea
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Rajmani RS, Gandham RK, Gupta SK, Sahoo AP, Singh PK, Saxena S, Kumar R, Chaturvedi U, Tiwari AK. Administration of IκB-kinase inhibitor PS1145 enhances apoptosis in DMBA-induced tumor in male Wistar rats. Cell Biol Int 2015; 39:1317-28. [DOI: 10.1002/cbin.10510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/30/2015] [Indexed: 11/11/2022]
Affiliation(s)
- R. S. Rajmani
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Ravi Kumar Gandham
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Shishir Kumar Gupta
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Aditya P. Sahoo
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Prafull Kumar Singh
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Shikha Saxena
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Rajiv Kumar
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Uttara Chaturvedi
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
| | - Ashok K. Tiwari
- Molecular Biology Laboratory; Indian Veterinary Research Institute; Izatnagar, Bareilly Uttar Pradesh India
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Pavlakis K, Bobos M, Batistatou A, Kotoula V, Eleftheraki AG, Stofas A, Timotheadou E, Pentheroudakis G, Psyrri A, Koutras A, Pectasides D, Papakostas P, Razis E, Christodoulou C, Kalogeras KT, Fountzilas G. p85 protein expression is associated with poor survival in HER2-positive patients with advanced breast cancer treated with trastuzumab. Pathol Oncol Res 2014; 21:273-82. [PMID: 25098276 DOI: 10.1007/s12253-014-9818-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/25/2014] [Indexed: 12/24/2022]
Abstract
To investigate the immunohistochemical expression of p85 in a cohort of trastuzumab-treated HER2-positive and HER2-negative metastatic breast cancer patients. The medical records of all patients with metastatic breast cancer treated with trastuzumab-based regimens between 1998 and 2010 were reviewed and clinical information was obtained. Formalin-fixed paraffin-embedded tumor tissue samples with adequate material were retrospectively collected from 183 patients. Samples were evaluated by immunohistochemistry for p85, estrogen receptors (ER), progesterone receptors (PgR), HER2, Ki67, PTEN and phosphorylated Akt (S473 and T308). HER2 status was studied by fluorescence in situ hybridization, as well. PIK3CA mutational status was also evaluated. Median follow-up for all patients was 72 months. Central re-evaluation for HER2 revealed only 111 HER2-positive cases, with the remaining 72 patients being HER2-negative. Median survival was longer in HER2-positive patients (50.7 months) compared to HER2-negative patients (36.6 months) both treated with trastuzumab, but this difference has not reached significance (p = 0.068). In total, 62% of the patients were found positive for p85, however the p85 protein was not found to be differentially expressed in HER2-positive versus HER2-negative cases. There were no significant associations between protein expression of p85 and any of the markers under study, or with time to progression. Positive p85 protein expression was however associated with poor survival in trastuzumab-treated HER2-positive patients. In our cohort of trastuzumab-treated HER2-positive breast cancer patients, positive p85 protein expression appears to be a prognostic factor of poor survival and, if validated, might have important implications in the treatment of such patients.
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Affiliation(s)
- Kitty Pavlakis
- Pathology Department, Athens University Medical School, Athens, Greece,
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Assessing the subcellular distribution of oncogenic phosphoinositide 3-kinase using microinjection into live cells. Biosci Rep 2014; 34:BSR20130133. [PMID: 27919038 PMCID: PMC3985441 DOI: 10.1042/bsr20130133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/18/2014] [Accepted: 03/04/2014] [Indexed: 02/07/2023] Open
Abstract
Oncogenic mutations in PIK3CA lead to an increase in intrinsic phosphoinositide kinase activity, but it is thought that increased access of PI3Kα (phosphoinositide 3-kinase α) to its PM (plasma membrane) localized substrate is also required for increased levels of downstream PIP3/Akt [phosphoinositide-3,4,5-trisphosphate/also called PKB (protein kinase B)] signalling. We have studied the subcellular localization of wild-type and the two most common oncogenic mutants of PI3Kα in cells maintained in growth media, and starved or stimulated cells using a novel method in which PI3Kα is pre-formed as a 1:1 p110α:p85α complex in vitro then introduced into live cells by microinjection. Oncogenic E545K and H1047R mutants did not constitutively interact with membrane lipids in vitro or in cells maintained in 10% (v/v) FBS. Following stimulation of RTKs (receptor tyrosine kinases), microinjected PI3Kα was recruited to the PM, but oncogenic forms of PI3Kα were not recruited to the PM to a greater extent and did not reside at the PM longer than the wild-type PI3Kα. Instead, the E545K mutant specifically bound activated Cdc42 in vitro and microinjection of E545K was associated with the formation of cellular protrusions, providing some preliminary evidence that changes in protein–protein interactions may play a role in the oncogenicity of the E545K mutant in addition to the well-known changes in lipid kinase activity. Oncogenic forms of PI3Kα (phosphoinositide 3-kinase α) microinjected into live cells are not recruited to the PM (plasma membrane) to a greater extent, and do not reside at the PM longer, than wild-type PI3Kα.
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Jeong D, Yi YS, Sung GH, Yang WS, Park JG, Yoon K, Yoon DH, Song C, Lee Y, Rhee MH, Kim TW, Kim JH, Cho JY. Anti-inflammatory activities and mechanisms of Artemisia asiatica ethanol extract. JOURNAL OF ETHNOPHARMACOLOGY 2014; 152:487-496. [PMID: 24503036 DOI: 10.1016/j.jep.2014.01.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/25/2014] [Accepted: 01/27/2014] [Indexed: 06/03/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Artemisia asiatica Nakai (Compositae) is a representative herbal plant used to treat infection and inflammatory diseases. Although Artemisia asiatica is reported to have immunopharmacological activities, the mechanisms of these activities and the effectiveness of Artemisia asiatica preparations in use are not known. MATERIALS AND METHODS To evaluate the anti-inflammatory activities of Artemisia asiatica ethanol extract (Aa-EE), we assayed nitric oxide (NO), tumor necrosis factor (TNF)-α, and prostaglandin E2 (PGE2) in macrophages and measured the extent of tissue injury in a model of gastric ulcer induced in mice by treatment with HCl in EtOH. Putative enzymatic mediators of Aa-EE activities were identified by nuclear fractionation, reporter gene assay, immunoprecipitation, immunoblotting, and kinase assay. Active compound in Aa-EE was identified using HPLC. RESULTS Treatment of RAW264.7 cells and peritoneal macrophages with Aa-EE suppressed the production of NO, PGE2, and TNF-α in response to lipopolysaccharide (LPS) and induced heme oxygenase-1 expression. The Aa-EE also ameliorated symptoms of gastric ulcer in HCl/EtOH-treated mice. These effects were associated with the inhibition of nuclear translocation of nuclear factor (NF)-κB and activator protein (AP)-1, implying that the anti-inflammatory action of the Aa-EE occurred through transcriptional inhibition. The upstream regulatory signals Syk and Src for translocation of NF-κB and TRAF6 for AP-1 were identified as targets of this effect. Analysis of Aa-EE by HPLC revealed the presence of luteolin, known to inhibit NO and PGE2 activity. CONCLUSION The anti-inflammatory activities attributed to Artemisia asiatica Nakai in traditional medicine may be mediated by luteolin through inhibition of Src/Syk/NF-κB and TRAF6/JNK/AP-1 signaling pathways.
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Affiliation(s)
- Deok Jeong
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Young-Su Yi
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Gi-Ho Sung
- Department of Herbal Crop Research, National Institutes of Horticultural & Herbal Science, Rural Development Administration, Suwon 441-707, Korea
| | - Woo Seok Yang
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Jae Gwang Park
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Keejung Yoon
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Deok Hyo Yoon
- Department of Biochemistry, Kangwon National University, Chuncehon 200-701, Republic of Korea
| | - Changsik Song
- Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Yunmi Lee
- Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea
| | - Man Hee Rhee
- College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Tae Woong Kim
- Department of Biochemistry, Kangwon National University, Chuncehon 200-701, Republic of Korea
| | - Jong-Hoon Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Biosafety Research Institute, Chonbuk National University, Jeonju 561-756, Republic of Korea.
| | - Jae Youl Cho
- Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
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Insulin activation of vacuolar protein sorting 34 mediates localized phosphatidylinositol 3-phosphate production at lamellipodia and activation of mTOR/S6K1. Cell Signal 2014; 26:1258-68. [PMID: 24582588 DOI: 10.1016/j.cellsig.2014.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 02/10/2014] [Accepted: 02/22/2014] [Indexed: 01/26/2023]
Abstract
The class III phosphatidylinositol 3-kinase, VPS34, phosphorylates the D3 hydroxyl of inositol generating phosphatidylinositol 3-phosphate (ptdins(3)p). Initial studies suggested that ptdins(3)p solely functioned as a component of vesicular and endosomal membranes and that VPS34 did not function in signal transduction. However, VPS34 has recently been shown to be required for insulin-mediated activation of S6 kinase 1 (S6K1). Whether VPS34 activity is directly regulated by insulin is unclear. It is also not known whether VPS34 activity can be spatially restricted in response to extracellular stimuli. Data presented here demonstrate that in response to insulin, VPS34 is activated and translocated to lamellipodia where it produces ptdins(3)p. The localized production of ptdins(3)p is dependent on Src phosphorylation of VPS34. In cells expressing VPS34 with mutations at Y231 or Y310, which are Src-phosphorylation sites, insulin-stimulated VPS34 translocation to the plasma membrane and lamellipodia formation are blocked. mTOR also colocalizes with VPS34 and ptdins(3)p at lamellipodia following insulin-stimulation. In cells expressing the VPS34-Y231F mutant, which blocks lamellipodia formation, mTOR localization at the plasma membrane and insulin-mediated S6K1 activation are reduced. This suggests that mTOR localization at lamellipodia is important for full activation of S6K1 induced by insulin. These data demonstrate that insulin can spatially regulate VPS34 activity through Src-mediated tyrosine phosphorylation and that this membrane localized activity contributes to lamellipodia formation and activation of mTOR/S6K1signaling.
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Zou W, Chen C, Zhong Y, An J, Zhang X, Yu Y, Yu Z, Fu J. PI3K/Akt pathway mediates Nrf2/ARE activation in human L02 hepatocytes exposed to low-concentration HBCDs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:12434-12440. [PMID: 24094245 DOI: 10.1021/es401791s] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigated the effects of hexabromocyclododecanes (HBCDs) at environmentally relevant concentrations on human L02 hepatocytes and explored possible underlying molecular mechanism(s), focusing on functional interactions between the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) and nuclear factor-erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathways. The results showed that low concentrations of HBCDs could stimulate cell proliferation in a "DNA-dependent protein kinase catalytic subunit" (DNA-PKcs)-dependent manner, increase protein levels and nuclear translocation of transcription factor Nrf2, and upregulate expression of its target gene heme oxygenase-1 (HO-1). Electrophoretic mobility-shift assays (EMSAs) showed that ARE was a prominent element for HO-1 induction after low-concentration HBCDs exposure. The relationship between PI3K/Akt pathway and Nrf2/HO-1 axis was demonstrated by the finding that pretreatment with PI3K inhibitors (wortmannin, LY294002) attenuated the upregulation of Nrf2 expression induced by HBCDs exposure. Furthermore, knock-down of DNA-PKcs through small interfering RNA blocked Nrf2/HO-1 axis activation in L02 cells exposed to low-concentration HBCDs. Moreover, DNA-PKcs and phosphorylated Akt at Ser(473) proved to be crucial in regulating the Nrf2-ARE pathway. Thus, the PI3K/Akt pathway is essential in regulating Nrf2-ARE pathway activation in L02 cells induced by low-concentration HBCDs.
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Affiliation(s)
- Wen Zou
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, P. R. China
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Vlug E, Ercan C, van der Wall E, van Diest PJ, Derksen PWB. Lobular Breast Cancer: Pathology, Biology, and Options for Clinical Intervention. Arch Immunol Ther Exp (Warsz) 2013; 62:7-21. [DOI: 10.1007/s00005-013-0251-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 08/05/2013] [Indexed: 12/13/2022]
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Genetic deregulation of the PIK3CA oncogene in oral cancer. Cancer Lett 2013; 338:193-203. [PMID: 23597702 DOI: 10.1016/j.canlet.2013.04.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 03/11/2013] [Accepted: 04/09/2013] [Indexed: 01/05/2023]
Abstract
The phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway is one of the most commonly deregulated pathways in human cancers. PI3K comprises a catalytic (p110α) and regulatory subunit (p85), and p110α is encoded by the PIK3CA gene. Here, we summarize the known genetic alterations, including amplifications and mutations, of the PIK3CA oncogene in oral cancer. We discuss in detail PIK3CA mutations and their mutual exclusivity with pathway genes in addition to the incidence of PIK3CA mutations in relation to ethnicity. We describe the constitutive activation of PI3K signaling, oncogenicity, and the genetic deregulation of the PIK3CA gene and its association with oral cancer disease stage. We emphasize the importance of therapeutically targeting the genetically deregulated PIK3CA oncogene and its signaling. We also discuss the implications of targeting Akt and/or mTOR, which are the downstream effectors of PI3K that may possibly pave the way for molecular therapeutic targets for PIK3CA-driven oral carcinogenesis. Furthermore, this critical review provides a complete picture of the PIK3CA oncogene and its deregulation in oral cancer, which may facilitate early diagnosis and improve prognosis through personalized molecular targeted therapy in oral cancer.
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CAPODANNO ALESSANDRA, BOLDRINI LAURA, ALÌ GRETA, PELLICCIONI SERENA, MUSSI ALFREDO, FONTANINI GABRIELLA. Phosphatidylinositol-3-kinase α catalytic subunit gene somatic mutations in bronchopulmonary neuroendocrine tumours. Oncol Rep 2012; 28:1559-66. [PMID: 22949056 PMCID: PMC3583575 DOI: 10.3892/or.2012.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 08/03/2012] [Indexed: 11/06/2022] Open
Abstract
Bronchopulmonary neuroendocrine tumours (BP-NETs) comprise a large spectrum of tumours including typical carcinoids (TCs), atypical carcinoids (ACs), large-cell neuroendocrine carcinomas (LCNECs) and small-cell lung carcinomas (SCLCs) that exhibit considerably different biological aggressiveness and clinical behaviours. The phosphatidylinositol-3-kinase α catalytic subunit (PIK3CA) gene is known to be involved in the pathogenesis of several types of human cancers through gene amplification, deletions or somatic missense mutations within the helical and catalytic domains. However, the PIK3CA gene status in BP-NETs has yet to be explored. This study aimed to investigate the PIK3CA gene status in a large series of BP-NETs by direct gene sequencing and to analyse its correlation with the main clinicopathological parameters. To the best of our knowledge, we demonstrated for the first time a high frequency of somatic missense mutations (23.2%) in the PIK3CA gene in a series of 190 BP-NETs, including 75 TCs, 23 ACs, 17 LCNECs and 75 SCLCs. The frequency of the PIK3CA gene mutation in the kinase domain was higher (17.9%) than that in the helical domain (5.3%). When the mutational status of the PIK3CA gene was compared with the main clinical and pathological characteristics of the BP-NET patients, we found a significant association between PIK3CA gene mutations and BP-NET histology (p=0.011). Interestingly, the frequency of PIK3CA gene mutations increased with the biological aggressiveness of all BP-NETs, except LCNECs. In conclusion, our results suggest that PIK3CA gene mutations may play a key role in tumourigenesis and aggressiveness of BP-NETs. The PIK3CA gene may represent a favourable candidate for an effective therapeutic strategy in the treatment of patients with BP-NETs.
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Affiliation(s)
- ALESSANDRA CAPODANNO
- Department of Surgery, Division of Pathological Anatomy, University of Pisa, I-56124 Pisa, Italy
| | - LAURA BOLDRINI
- Department of Surgery, Division of Pathological Anatomy, University of Pisa, I-56124 Pisa, Italy
| | - GRETA ALÌ
- Department of Surgery, Division of Pathological Anatomy, University of Pisa, I-56124 Pisa, Italy
| | - SERENA PELLICCIONI
- Department of Surgery, Division of Pathological Anatomy, University of Pisa, I-56124 Pisa, Italy
| | - ALFREDO MUSSI
- Department of Cardio-Thoracic Surgery, Division of Thoracic Surgery, University of Pisa, I-56124 Pisa, Italy
| | - GABRIELLA FONTANINI
- Department of Surgery, Division of Pathological Anatomy, University of Pisa, I-56124 Pisa, Italy
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Rios JJ, Paria N, Burns DK, Israel BA, Cornelia R, Wise CA, Ezaki M. Somatic gain-of-function mutations in PIK3CA in patients with macrodactyly. Hum Mol Genet 2012; 22:444-51. [PMID: 23100325 PMCID: PMC3542862 DOI: 10.1093/hmg/dds440] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Macrodactyly is a discrete congenital anomaly consisting of enlargement of all tissues localized to the terminal portions of a limb, typically within a ‘nerve territory’. The classic terminology for this condition is ‘lipofibromatous hamartoma of nerve’ or Type I macrodactyly. The peripheral nerve, itself, is enlarged both in circumference and in length. It is not related to neurofibromatosis (NF1), nor is it associated with vascular malformations, such as in the recently reported CLOVES syndrome. The specific nerve pathophysiology in this form of macrodactyly has not been well described and a genetic etiology for this specific form of enlargement is unknown. To identify the genetic cause of macrodactyly, we used whole-exome sequencing to identify somatic mutations present in the affected nerve of a single patient. We confirmed a novel mutation in PIK3CA (R115P) present in the patient's affected nerve tissue but not in blood DNA. Sequencing PIK3CA exons identified gain-of-function mutations (E542K, H1047L or H1047R) in the affected tissue of five additional unrelated patients; mutations were absent in blood DNA available from three patients. Immunocytochemistry confirmed AKT activation in cultured cells from the nerve of a macrodactyly patient. Additionally, we found that the most abnormal structure within the involved nerve in a macrodactylous digit is the perineurium, with additional secondary effects on the axon number and size. Thus, isolated congenital macrodactyly is caused by somatic activation of the PI3K/AKT cell-signaling pathway and is genetically and biochemically related to other overgrowth syndromes.
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Affiliation(s)
- Jonathan J Rios
- Sarah M and Charles E Seay Center for Musculoskeletal Research, Texas Scottish Rite Hospital for Children, Dallas, TX 75219, USA.
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Burke JE, Williams RL. Dynamic steps in receptor tyrosine kinase mediated activation of class IA phosphoinositide 3-kinases (PI3K) captured by H/D exchange (HDX-MS). Adv Biol Regul 2012. [PMID: 23194976 PMCID: PMC3613897 DOI: 10.1016/j.jbior.2012.09.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The catalytic subunits of all class IA phosphoinositide 3-kinases (PI3Ks) associate with identical p85-related subunits and phosphorylate PIP2 yielding PIP3, but they can vary greatly in the signaling pathways in which they participate. The binding of the p85 subunit to the p110 catalytic subunits is constitutive, and this inhibits activity, but some of the inhibitory contacts are reversible and subject to regulation. Interaction with phosphotyrosine-containing peptides (RTK-pY) releases a subset of these inhibitory contacts. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) provides a map of the dynamic interactions unique to each of the isotypes. RTK-pY binding exposes the p110 helical domains for all class IA enzymes (due to release of the nSH2 contact) and exposes the C-lobe of the kinase domains of p110β and p110δ (resulting from release of the cSH2 contact). Consistent with this, our in vitro assays show that all class IA isoforms are inhibited by the nSH2, but only p110β and p110δ are inhibited by the cSH2. While a C2/iSH2 inhibitory contact exists in all isoforms, HDX indicates that p110β releases this contact most readily. The unique dynamic relationships of the different p110 isozymes to the p85 subunit may facilitate new strategies for specific inhibitors of the PI3Ks.
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Affiliation(s)
- John E Burke
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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40
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McCubrey JA, Steelman LS, Chappell WH, Abrams SL, Montalto G, Cervello M, Nicoletti F, Fagone P, Malaponte G, Mazzarino MC, Candido S, Libra M, Bäsecke J, Mijatovic S, Maksimovic-Ivanic D, Milella M, Tafuri A, Cocco L, Evangelisti C, Chiarini F, Martelli AM. Mutations and deregulation of Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades which alter therapy response. Oncotarget 2012; 3:954-87. [PMID: 23006971 PMCID: PMC3660063 DOI: 10.18632/oncotarget.652] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/17/2012] [Indexed: 02/07/2023] Open
Abstract
The Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades are often activated by genetic alterations in upstream signaling molecules such as receptor tyrosine kinases (RTK). Certain components of these pathways, RAS, NF1, BRAF, MEK1, DUSP5, PP2A, PIK3CA, PIK3R1, PIK3R4, PIK3R5, IRS4, AKT, NFKB1, MTOR, PTEN, TSC1, and TSC2 may also be activated/inactivated by mutations or epigenetic silencing. Upstream mutations in one signaling pathway or even in downstream components of the same pathway can alter the sensitivity of the cells to certain small molecule inhibitors. These pathways have profound effects on proliferative, apoptotic and differentiation pathways. Dysregulation of components of these cascades can contribute to: resistance to other pathway inhibitors, chemotherapeutic drug resistance, premature aging as well as other diseases. This review will first describe these pathways and discuss how genetic mutations and epigenetic alterations can result in resistance to various inhibitors.
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Affiliation(s)
- James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA.
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41
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Roop RP, Ma CX. Endocrine resistance in breast cancer: molecular pathways and rational development of targeted therapies. Future Oncol 2012; 8:273-92. [PMID: 22409464 DOI: 10.2217/fon.12.8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Endocrine resistance presents a major challenge in the management of estrogen receptor (ER)-positive breast cancer and is an area under intense investigation. Although the underlying mechanism is still poorly understood, many studies point towards the 'cross-talk' between ER and growth factor receptor signaling pathways as the key in the development of estrogen-independent growth in breast cancer. This review aims to provide the reader our current understanding of various molecular pathways that mediate endocrine resistance and that are being evaluated as therapeutic targets for ER-positive breast cancer. While most of the agents that target these pathways have only been tested in Phase I or small Phase II trials, some have shown encouraging results. A critical issue that remains is the development of research strategies and clinical trials that take into account the molecular heterogeneity of ER-positive breast cancer.
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Affiliation(s)
- Ryan P Roop
- Washington University School of Medicine in Saint Louis, Department of Medicine, Divisions of Hematology & Oncology, St Louis, MO, USA
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Norman P. Evaluation of WO2012037204 and WO2012037226: Exelixis' selective PI3Kδ inhibitors; the basis of a US$251 million deal. Expert Opin Ther Pat 2012; 22:971-6. [DOI: 10.1517/13543776.2012.701282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Leystra AA, Deming DA, Zahm CD, Farhoud M, Olson TJP, Hadac JN, Nettekoven LA, Albrecht DM, Clipson L, Sullivan R, Washington MK, Torrealba JR, Weichert JP, Halberg RB. Mice expressing activated PI3K rapidly develop advanced colon cancer. Cancer Res 2012; 72:2931-6. [PMID: 22525701 DOI: 10.1158/0008-5472.can-11-4097] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aberrations in the phosphoinositide 3-kinase (PI3K) signaling pathway play a key role in the pathogenesis of numerous cancers by altering cellular growth, metabolism, proliferation, and apoptosis. Mutations in the catalytic domain of PI3K that generate a dominantly active kinase are commonly found in human colorectal cancers and have been thought to drive tumor progression but not initiation. However, the effects of constitutively activated PI3K upon the intestinal mucosa have not been previously studied in animal models. Here, we show that the expression of a dominantly active form of the PI3K protein in the mouse intestine results in hyperplasia and advanced neoplasia. Mice expressing constitutively active PI3K in the epithelial cells of the distal small bowel and colon rapidly developed invasive adenocarcinomas in the colon that spread into the mesentery and adjacent organs. The histologic characteristics of these tumors were strikingly similar to invasive mucinous colon cancers in humans. Interestingly, these tumors formed without a benign polypoid intermediary, consistent with the lack of aberrant WNT signaling observed. Together, our findings indicate a noncanonical mechanism of colon tumor initiation that is mediated through activation of PI3K. This unique model has the potential to further our understanding of human disease and facilitate the development of therapeutics through pharmacologic screening and biomarker identification.
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Affiliation(s)
- Alyssa A Leystra
- Department of Oncology, University of Wisconsin, Madison 53792, USA
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44
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Abstract
Phosphoinositide 3-kinases (PI3Ks) control cell growth, proliferation, cell survival, metabolic activity, vesicular trafficking, degranulation, and migration. Through these processes, PI3Ks modulate vital physiology. When over-activated in disease, PI3K promotes tumor growth, angiogenesis, metastasis or excessive immune cell activation in inflammation, allergy and autoimmunity. This chapter will introduce molecular activation and signaling of PI3Ks, and connections to target of rapamycin (TOR) and PI3K-related protein kinases (PIKKs). The focus will be on class I PI3Ks, and extend into current developments to exploit mechanistic knowledge for therapy.
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Affiliation(s)
- Matthias Wymann
- Institute Biochemistry & Genetics, Department Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland,
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Burke JE, Vadas O, Berndt A, Finegan T, Perisic O, Williams RL. Dynamics of the phosphoinositide 3-kinase p110δ interaction with p85α and membranes reveals aspects of regulation distinct from p110α. Structure 2011; 19:1127-37. [PMID: 21827948 PMCID: PMC3155019 DOI: 10.1016/j.str.2011.06.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 05/06/2011] [Accepted: 06/07/2011] [Indexed: 12/12/2022]
Abstract
Phosphoinositide 3-kinase δ is upregulated in lymphocytic leukemias. Because the p85-regulatory subunit binds to any class IA subunit, it was assumed there is a single universal p85-mediated regulatory mechanism; however, we find isozyme-specific inhibition by p85α. Using deuterium exchange mass spectrometry (DXMS), we mapped regulatory interactions of p110δ with p85α. Both nSH2 and cSH2 domains of p85α contribute to full inhibition of p110δ, the nSH2 by contacting the helical domain and the cSH2 via the C terminus of p110δ. The cSH2 inhibits p110β and p110δ, but not p110α, implying that p110α is uniquely poised for oncogenic mutations. Binding RTK phosphopeptides disengages the SH2 domains, resulting in exposure of the catalytic subunit. We find that phosphopeptides greatly increase the affinity of the heterodimer for PIP2-containing membranes measured by FRET. DXMS identified regions decreasing exposure at membranes and also regions gaining exposure, indicating loosening of interactions within the heterodimer at membranes.
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Affiliation(s)
- John E Burke
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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Steelman LS, Chappell WH, Abrams SL, Kempf RC, Long J, Laidler P, Mijatovic S, Maksimovic-Ivanic D, Stivala F, Mazzarino MC, Donia M, Fagone P, Malaponte G, Nicoletti F, Libra M, Milella M, Tafuri A, Bonati A, Bäsecke J, Cocco L, Evangelisti C, Martelli AM, Montalto G, Cervello M, McCubrey JA. Roles of the Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR pathways in controlling growth and sensitivity to therapy-implications for cancer and aging. Aging (Albany NY) 2011; 3:192-222. [PMID: 21422497 PMCID: PMC3091517 DOI: 10.18632/aging.100296] [Citation(s) in RCA: 449] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dysregulated signaling through the Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR pathways is often the result of genetic alterations in critical components in these pathways or upstream activators. Unrestricted cellular proliferation and decreased sensitivity to apoptotic-inducing agents are typically associated with activation of these pro-survival pathways. This review discusses the functions these pathways have in normal and neoplastic tissue growth and how they contribute to resistance to apoptotic stimuli. Crosstalk and commonly identified mutations that occur within these pathways that contribute to abnormal activation and cancer growth will also be addressed. Finally the recently described roles of these pathways in cancer stem cells, cellular senescence and aging will be evaluated. Controlling the expression of these pathways could ameliorate human health.
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Affiliation(s)
- Linda S Steelman
- Department of Microbiology and Immunology, East Carolina University, Greenville, NC 27858, USA
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Stehr H, Jang SHJ, Duarte JM, Wierling C, Lehrach H, Lappe M, Lange BMH. The structural impact of cancer-associated missense mutations in oncogenes and tumor suppressors. Mol Cancer 2011; 10:54. [PMID: 21575214 PMCID: PMC3123651 DOI: 10.1186/1476-4598-10-54] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 05/16/2011] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Current large-scale cancer sequencing projects have identified large numbers of somatic mutations covering an increasing number of different cancer tissues and patients. However, the characterization of these mutations at the structural and functional level remains a challenge. RESULTS We present results from an analysis of the structural impact of frequent missense cancer mutations using an automated method. We find that inactivation of tumor suppressors in cancer correlates frequently with destabilizing mutations preferably in the core of the protein, while enhanced activity of oncogenes is often linked to specific mutations at functional sites. Furthermore, our results show that this alteration of oncogenic activity is often associated with mutations at ATP or GTP binding sites. CONCLUSIONS With our findings we can confirm and statistically validate the hypotheses for the gain-of-function and loss-of-function mechanisms of oncogenes and tumor suppressors, respectively. We show that the distinct mutational patterns can potentially be used to pre-classify newly identified cancer-associated genes with yet unknown function.
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Affiliation(s)
- Henning Stehr
- Max-Planck Institute for Molecular Genetics, Structural Proteomics/Bioinformatics Group, Otto-Warburg Laboratory, Boltzmannstrasse 12, 14195 Berlin, Germany
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Vogt PK, Hart JR, Gymnopoulos M, Jiang H, Kang S, Bader AG, Zhao L, Denley A. Phosphatidylinositol 3-kinase: the oncoprotein. Curr Top Microbiol Immunol 2011; 347:79-104. [PMID: 20582532 DOI: 10.1007/82_2010_80] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The catalytic and regulatory subunits of class I phosphoinositide 3-kinase (PI3K) have oncogenic potential. The catalytic subunit p110α and the regulatory subunit p85 undergo cancer-specific gain-of-function mutations that lead to enhanced enzymatic activity, ability to signal constitutively, and oncogenicity. The β, γ, and δ isoforms of p110 are cell-transforming as overexpressed wild-type proteins. Class I PI3Ks have the unique ability to generate phosphoinositide 3,4,5 trisphosphate (PIP(3)). Class II and class III PI3Ks lack this ability. Genetic and cell biological evidence suggests that PIP(3) is essential for PI3K-mediated oncogenicity, explaining why class II and class III enzymes have not been linked to cancer. Mutational analysis reveals the existence of at least two distinct molecular mechanisms for the gain of function seen with cancer-specific mutations in p110α; one causing independence from upstream receptor tyrosine kinases, the other inducing independence from Ras. An essential component of the oncogenic signal that is initiated by PI3K is the TOR (target of rapamycin) kinase. TOR is an integrator of growth and of metabolic inputs. In complex with the raptor protein (TORC1), it controls cap-dependent translation, and this function is essential for PI3K-initiated oncogenesis.
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Affiliation(s)
- Peter K Vogt
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Gabelli SB, Huang CH, Mandelker D, Schmidt-Kittler O, Vogelstein B, Amzel LM. Structural effects of oncogenic PI3Kα mutations. Curr Top Microbiol Immunol 2011; 347:43-53. [PMID: 20593314 DOI: 10.1007/82_2010_53] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Physiological activation of PI3Kα is brought about by the release of the inhibition by p85 when the nSH2 binds the phosphorylated tyrosine of activated receptors or their substrates. Oncogenic mutations of PI3Kα result in a constitutively activated enzyme that triggers downstream pathways that increase tumor aggressiveness and survival. Structural information suggests that some mutations also activate the enzyme by releasing p85 inhibition. Other mutations work by different mechanisms. For example, the most common mutation, His1047Arg, causes a conformational change that increases membrane association resulting in greater accessibility to the substrate, an integral membrane component. These effects are examples of the subtle structural changes that result in increased activity. The structures of these and other mutants are providing the basis for the design of isozyme-specific, mutation-specific inhibitors for individualized cancer therapies.
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Affiliation(s)
- Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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50
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The Role of PIK3CA Mutations as A Predictor of Outcomes and A Therapeutic Target. CURRENT BREAST CANCER REPORTS 2010. [DOI: 10.1007/s12609-010-0022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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