1
|
Mir-30b-5p Promotes Proliferation, Migration, and Invasion of Breast Cancer Cells via Targeting ASPP2. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7907269. [PMID: 32420372 PMCID: PMC7210518 DOI: 10.1155/2020/7907269] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/06/2020] [Accepted: 01/16/2020] [Indexed: 12/18/2022]
Abstract
Triple-negative breast cancer (TNBC) is the most aggressive subtypes of breast cancer, which has few effective targeted therapies. Various sources of evidence confirm that microRNAs (miRNAs) contribute to the progression and metastasis of human breast cancer. However, the molecular mechanisms underlying the changes in miRNAs expression and the regulation of miRNAs functions have not been well clarified. In this study, we found that the expression of miR-30b-5p was upregulated in breast cancer tissues and breast cancer cell lines, compared to paracancer tissues and normal breast cell lines. Moreover, induced overexpression of miR-30b-5p promoted the MDA-MB-231 and HCC 1937 cell growth, migration, and invasion and reduced the cellular apoptosis. Further studies confirmed that miR-30b-5p could directly target ASPP2 and then activate the AKT signaling pathway. Our results suggested that miR-30b-5p could act as a tumor promoter in TNBC. The newly identified miR-30b-5p/ASPP2/AKT axis represents a novel therapeutic strategy for treating TNBC.
Collapse
|
2
|
Van Hook K, Wang Z, Chen D, Nold C, Zhu Z, Anur P, Lee HJ, Yu Z, Sheppard B, Dai MS, Sears R, Spellman P, Lopez CD. ΔN-ASPP2, a novel isoform of the ASPP2 tumor suppressor, promotes cellular survival. Biochem Biophys Res Commun 2016; 482:1271-1277. [PMID: 27939881 DOI: 10.1016/j.bbrc.2016.12.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022]
Abstract
ASPP2 is a tumor suppressor that works, at least in part, through enhancing p53-dependent apoptosis. We now describe a new ASPP2 isoform, ΔN-ASPP2, generated from an internal transcription start site that encodes an N-terminally truncated protein missing a predicted 254 amino acids. ΔN-ASPP2 suppresses p53 target gene transactivation, promoter occupancy, and endogenous p53 target gene expression in response to DNA damage. Moreover, ΔN-ASPP2 promotes progression through the cell cycle, as well as resistance to genotoxic stress-induced growth inhibition and apoptosis. Additionally, we found that ΔN-ASPP2 expression is increased in human breast tumors as compared to adjacent normal breast tissue; in contrast, ASPP2 is suppressed in the majority of these breast tumors. Together, our results provide insight into how this new ASPP2 isoform may play a role in regulating the ASPP2-p53 axis.
Collapse
Affiliation(s)
- Kathryn Van Hook
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Zhiping Wang
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Dexi Chen
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA; Beijing Institute of Hepatology, Beijing You'an Hospital, Capital Medical University, Beijing, 100069, China
| | - Casey Nold
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Zhiyi Zhu
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Pavana Anur
- Department of Molecular and Medical Genetics and the Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Hun-Joo Lee
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Zhiyong Yu
- Shandong Tumor Hospital and Institute, Jinan, 250117, China
| | - Brett Sheppard
- Department of Surgery and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Mu-Shui Dai
- Department of Molecular and Medical Genetics and the Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Rosalie Sears
- Department of Molecular and Medical Genetics and the Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Paul Spellman
- Department of Molecular and Medical Genetics and the Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Charles D Lopez
- Department of Medicine, Division of Hematology and Medical Oncology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA.
| |
Collapse
|
3
|
Posada IMD, Serulla M, Zhou Y, Oetken-Lindholm C, Abankwa D, Lectez B. ASPP2 Is a Novel Pan-Ras Nanocluster Scaffold. PLoS One 2016; 11:e0159677. [PMID: 27437940 PMCID: PMC4954646 DOI: 10.1371/journal.pone.0159677] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/06/2016] [Indexed: 02/02/2023] Open
Abstract
Ras-induced senescence mediated through ASPP2 represents a barrier to tumour formation. It is initiated by ASPP2’s interaction with Ras at the plasma membrane, which stimulates the Raf/MEK/ERK signaling cascade. Ras to Raf signalling requires Ras to be organized in nanoscale signalling complexes, called nanocluster. We therefore wanted to investigate whether ASPP2 affects Ras nanoclustering. Here we show that ASPP2 increases the nanoscale clustering of all oncogenic Ras isoforms, H-ras, K-ras and N-ras. Structure-function analysis with ASPP2 truncation mutants suggests that the nanocluster scaffolding activity of ASPP2 converges on its α-helical domain. While ASPP2 increased effector recruitment and stimulated ERK and AKT phosphorylation, it did not increase colony formation of RasG12V transformed NIH/3T3 cells. By contrast, ASPP2 was able to suppress the transformation enhancing ability of the nanocluster scaffold Gal-1, by competing with the specific effect of Gal-1 on H-rasG12V- and K-rasG12V-nanoclustering, thus imposing ASPP2’s ERK and AKT signalling signature. Similarly, ASPP2 robustly induced senescence and strongly abrogated mammosphere formation irrespective of whether it was expressed alone or together with Gal-1, which by itself showed the opposite effect in Ras wt or H-ras mutant breast cancer cells. Our results suggest that Gal-1 and ASPP2 functionally compete in nanocluster for active Ras on the plasma membrane. ASPP2 dominates the biological outcome, thus switching from a Gal-1 supported growth-promoting setting to a senescence inducing and stemness suppressive program in cancer cells. Our results support Ras nanocluster as major integrators of tumour fate decision events.
Collapse
Affiliation(s)
- Itziar M. D. Posada
- Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520, Turku, Finland
| | - Marc Serulla
- Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520, Turku, Finland
| | - Yong Zhou
- University of Texas Health Science Center at Houston, Medical School, Houston, Texas, United States of America
| | | | - Daniel Abankwa
- Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520, Turku, Finland
- * E-mail:
| | - Benoît Lectez
- Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520, Turku, Finland
| |
Collapse
|
4
|
Highly homologous proteins exert opposite biological activities by using different interaction interfaces. Sci Rep 2015; 5:11629. [PMID: 26130271 PMCID: PMC4486954 DOI: 10.1038/srep11629] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/02/2015] [Indexed: 11/08/2022] Open
Abstract
We present a possible molecular basis for the opposite activity of two homologues proteins that bind similar ligands and show that this is achieved by fine-tuning of the interaction interface. The highly homologous ASPP proteins have opposite roles in regulating apoptosis: ASPP2 induces apoptosis while iASPP inhibits it. The ASPP proteins are regulated by an autoinhibitory interaction between their Ank-SH3 and Pro domains. We performed a detailed biophysical and molecular study of the Pro - Ank-SH3 interaction in iASPP and compared it to the interaction in ASPP2. We found that iASPP Pro is disordered and that the interaction sites are entirely different: iASPP Ank-SH3 binds iASPP Pro via its fourth Ank repeat and RT loop while ASPP2 Ank-SH3 binds ASPP2 Pro via its first Ank repeat and the n-src loop. It is possible that by using different moieties in the same interface, the proteins can have distinct and specific interactions resulting in differential regulation and ultimately different biological activities.
Collapse
|
5
|
Reingewertz TH, Iosub-Amir A, Bonsor DA, Mayer G, Amartely H, Friedler A, Sundberg EJ. An Intrinsically Disordered Region in the Proapoptotic ASPP2 Protein Binds to the Helicobacter pylori Oncoprotein CagA. Biochemistry 2015; 54:3337-47. [PMID: 25963096 DOI: 10.1021/acs.biochem.5b00084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The leading risk factor for gastric cancer in humans is infection by Helicobacter pylori strains that express and translocate the oncoprotein CagA into host epithelial cells. Once inside host cells, CagA interacts with ASPP2, which specifically stimulates p53-mediated apoptosis and reverses its pro-apoptotic function to promote ASPP2-dependent degradation of p53. The X-ray crystal structure of a complex between the N-terminal domain of CagA and a 56-residue fragment of ASPP2, of which 22 residues were resolved, was recently described. Here, we present biochemical and biophysical analyses of the interaction between the additional regions of CagA and ASPP2 potentially involved in this interaction. Using size exclusion chromatography-multiangle laser light scattering, circular dichroism, and nuclear magnetic resonance analyses, we observed that the ASPP2 region spanning residues 331-692, which was not part of the ASPP2 fragment used for crystallization, is intrinsically disordered in its unbound state. By surface plasmon resonance analysis and isothermal titration calorimetry, we found that a portion of this disordered region in ASPP2, residues 448-692, binds to the N-terminal domain of CagA. We also measured the affinity of the complex between the ASPP2 fragment composed of residues 693-918 and inclusive of the fragment used for crystallization and CagA. Additionally, we mapped the binding regions between ASPP2 and CagA using peptide arrays, demonstrating interactions between CagA and numerous peptides distributed throughout the ASPP2 protein sequence. Our results identify previously uncharacterized regions distributed throughout the protein sequence of ASPP2 as determinants of CagA binding, providing mechanistic insight into apoptosis reprogramming by CagA and potential new drug targets for H. pylori-mediated gastric cancer.
Collapse
Affiliation(s)
| | - Anat Iosub-Amir
- ‡Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | - Guy Mayer
- ‡Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Hadar Amartely
- ‡Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Assaf Friedler
- ‡Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | |
Collapse
|
6
|
Xie F, Jia L, Lin M, Shi Y, Yin J, Liu Y, Chen D, Meng Q. ASPP2 attenuates triglycerides to protect against hepatocyte injury by reducing autophagy in a cell and mouse model of non-alcoholic fatty liver disease. J Cell Mol Med 2014; 19:155-64. [PMID: 25256142 PMCID: PMC4288359 DOI: 10.1111/jcmm.12364] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/10/2014] [Indexed: 01/01/2023] Open
Abstract
ASPP2 is a pro-apoptotic member of the p53 binding protein family. ASPP2 has been shown to inhibit autophagy, which maintains energy balance in nutritional deprivation. We attempted to identify the role of ASPP2 in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). In a NAFLD cell model, control treated and untreated HepG2 cells were pre-incubated with GFP-adenovirus (GFP-ad) for 12 hrs and then treated with oleic acid (OA) for 24 hrs. In the experimental groups, the HepG2 cells were pre-treated with ASPP2-adenovirus (ASPP2-ad) or ASPP2-siRNA for 12 hrs and then treated with OA for 24 hrs. BALB/c mice fed a methionine- and choline-deficient (MCD) diet were used to generate a mouse model of NAFLD. The mice with fatty livers in the control group were pre-treated with injections of GFP-ad for 10 days. In the experimental group, the mice that had been pre-treated with ASPP2-ad were fed an MCD diet for 10 days. ASPP2-ad or GFP-ad was administered once every 5 days. Liver tissue from fatty liver patients and healthy controls were used to analyse the role of ASPP2. Autophagy, apoptosis markers and lipid metabolism mediators, were assessed with confocal fluorescence microscopy, immunohistochemistry, western blot and biochemical assays. ASPP2 overexpression decreased the triglyceride content and inhibited autophagy and apoptosis in the HepG2 cells. ASPP2-ad administration suppressed the MCD diet-induced autophagy, steatosis and apoptosis and decreased the previously elevated alanine aminotransferase levels. In conclusion, ASPP2 may participate in the lipid metabolism of non-alcoholic steatohepatitis and attenuate liver failure.
Collapse
Affiliation(s)
- Fang Xie
- Beijing You An Hospital, Affiliated Hospital of Capital Medical University, Beijing, China; Beijing Institute of Hepatology, Beijing, China
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Liu C, Luan J, Bai Y, Li Y, Lu L, Liu Y, Hakuno F, Takahashi SI, Duan C, Zhou J. Aspp2 negatively regulates body growth but not developmental timing by modulating IRS signaling in zebrafish embryos. Gen Comp Endocrinol 2014; 197:82-91. [PMID: 24362258 DOI: 10.1016/j.ygcen.2013.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/22/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
The growth and developmental rate of developing embryos and fetus are tightly controlled and coordinated to maintain proper body shape and size. The insulin receptor substrate (IRS) proteins, key intracellular transducers of insulin and insulin-like growth factor signaling, play essential roles in the regulation of growth and development. A short isoform of apoptosis-stimulating protein of p53 2 (ASPP2) was recently identified as a binding partner of IRS-1 and IRS-2 in mammalian cells in vitro. However, it is unclear whether ASPP2 plays any role in vertebrate embryonic growth and development. Here, we show that zebrafish Aspp2a and Aspp2b negatively regulate embryonic growth without affecting developmental rate. Human ASPP2 had similar effects on body growth in zebrafish embryos. Aspp2a and 2b inhibit Akt signaling. This inhibition was reversed by coinjection of myr-Akt1, a constitutively active form of Akt1. Zebrafish Aspp2a and Aspp2b physically bound with Irs-1, and the growth inhibitory effects of ASPP2/Aspp2 depend on the presence of their ankyrin repeats and SH3 domains. These findings uncover a novel role of Aspp2 in regulating vertebrate embryonic growth.
Collapse
Affiliation(s)
- Chengdong Liu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Jing Luan
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yan Bai
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yun Li
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Ling Lu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yunzhang Liu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Fumihiko Hakuno
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shin-Ichiro Takahashi
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology (C.D.), University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Zhou
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
| |
Collapse
|
8
|
Iosub-Amir A, Friedler A. Protein–protein interactions of ASPP2: an emerging therapeutic target. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00147h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ASPP2 induces apoptosis and is downregulated in many types of cancer, making it a promising target for anti-cancer drugs.
Collapse
Affiliation(s)
- Anat Iosub-Amir
- Institute of Chemistry
- The Hebrew University of Jerusalem
- Safra Campus
- Jerusalem 91904, Israel
| | - Assaf Friedler
- Institute of Chemistry
- The Hebrew University of Jerusalem
- Safra Campus
- Jerusalem 91904, Israel
| |
Collapse
|
9
|
Rotem-Bamberger S, Katz C, Friedler A. Regulation of ASPP2 interaction with p53 core domain by an intramolecular autoinhibitory mechanism. PLoS One 2013; 8:e58470. [PMID: 23472201 PMCID: PMC3589414 DOI: 10.1371/journal.pone.0058470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/06/2013] [Indexed: 11/30/2022] Open
Abstract
ASPP2 is a key protein in regulating apoptosis both in p53-dependent and-independent pathways. The C-terminal part of ASPP2 contains four ankyrin repeats and an SH3 domain (Ank-SH3) that mediate the interactions of ASPP2 with apoptosis related proteins such as p53, Bcl-2 and the p65 subunit of NFκB. p53 core domain (p53CD) binds the n-src loop and the RT loop of ASPP2 SH3. ASPP2 contains a disordered proline rich domain (ASPP2 Pro) that forms an intramolecular autoinhibitory interaction with the Ank-SH3 domains. Here we show how this intramolecular interaction affects the intermolecular interactions of ASPP2 with p53, Bcl-2 and NFkB. We used biophysical methods to obtain better understanding of the relationship between ASPP2 and its partners for getting a comprehensive view on ASPP2 pathways. Fluorescence anisotropy competition experiments revealed that both ASPP2 Pro and p53CD competed for binding the n-src loop of the ASPP2 SH3, indicating regulation of p53CD binding to this loop by ASPP2 Pro. Peptides derived from the ASPP2-binding interface of Bcl-2 did not compete with p53CD or NFkB peptides for binding the ASPP2 n-src loop. However, p53CD displaced the NFκB peptide (residues 303–332) from its complex with ASPP2 Ank-SH3, indicating that NFκB 303–332 and p53CD bind a partly overlapping site in ASPP2 SH3, mostly in the RT loop. These results are in agreement with previous docking studies, which showed that ASPP2 Ank-SH3 binds Bcl-2 and NFκB mostly via distinct sites from p53. However they show some overlap between the binding sites of p53CD and NFkB in ASPP2 Ank-SH3. Our results provide experimental evidence that the intramolecular interaction in ASPP2 regulates its binding to p53CD and that ASPP2 Ank-SH3 binds Bcl-2 and NFκB via distinct sites.
Collapse
Affiliation(s)
- Shahar Rotem-Bamberger
- Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Chen Katz
- Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Assaf Friedler
- Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
- * E-mail:
| |
Collapse
|
10
|
ASPP1 and ASPP2 bind active RAS, potentiate RAS signalling and enhance p53 activity in cancer cells. Cell Death Differ 2013; 20:525-34. [PMID: 23392125 PMCID: PMC3595493 DOI: 10.1038/cdd.2013.3] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
RAS mutations occur frequently in human cancer and activated RAS signalling contributes to tumour development and progression. Apart from its oncogenic effects on cell growth, active RAS has tumour-suppressive functions via its ability to induce cellular senescence and apoptosis. RAS is known to induce p53-dependent cell cycle arrest, yet its effect on p53-dependent apoptosis remains unclear. We report here that apoptosis-stimulating protein of p53 (ASPP) 1 and 2, two activators of p53, preferentially bind active RAS via their N-terminal RAS-association domains (RAD). Additionally, ASPP2 colocalises with and contributes to RAS cellular membrane localisation and potentiates RAS signalling. In cancer cells, ASPP1 and ASPP2 cooperate with oncogenic RAS to enhance the transcription and apoptotic function of p53. Thus, loss of ASPP1 and ASPP2 in human cancer cells may contribute to the full transforming property of RAS oncogene.
Collapse
|
11
|
N terminus of ASPP2 binds to Ras and enhances Ras/Raf/MEK/ERK activation to promote oncogene-induced senescence. Proc Natl Acad Sci U S A 2012; 110:312-7. [PMID: 23248303 DOI: 10.1073/pnas.1201514110] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The ASPP2 (also known as 53BP2L) tumor suppressor is a proapoptotic member of a family of p53 binding proteins that functions in part by enhancing p53-dependent apoptosis via its C-terminal p53-binding domain. Mounting evidence also suggests that ASPP2 harbors important nonapoptotic p53-independent functions. Structural studies identify a small G protein Ras-association domain in the ASPP2 N terminus. Because Ras-induced senescence is a barrier to tumor formation in normal cells, we investigated whether ASPP2 could bind Ras and stimulate the protein kinase Raf/MEK/ERK signaling cascade. We now show that ASPP2 binds to Ras-GTP at the plasma membrane and stimulates Ras-induced signaling and pERK1/2 levels via promoting Ras-GTP loading, B-Raf/C-Raf dimerization, and C-Raf phosphorylation. These functions require the ASPP2 N terminus because BBP (also known as 53BP2S), an alternatively spliced ASPP2 isoform lacking the N terminus, was defective in binding Ras-GTP and stimulating Raf/MEK/ERK signaling. Decreased ASPP2 levels attenuated H-RasV12-induced senescence in normal human fibroblasts and neonatal human epidermal keratinocytes. Together, our results reveal a mechanism for ASPP2 tumor suppressor function via direct interaction with Ras-GTP to stimulate Ras-induced senescence in nontransformed human cells.
Collapse
|
12
|
Wang L, Xing H, Tian Z, Peng L, Li Y, Tang K, Rao Q, Wang M, Wang J. iASPPsv antagonizes apoptosis induced by chemotherapeutic agents in MCF-7 cells and mouse thymocytes. Biochem Biophys Res Commun 2012; 424:414-20. [DOI: 10.1016/j.bbrc.2012.06.124] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 06/25/2012] [Indexed: 12/30/2022]
|
13
|
Autophagic activity dictates the cellular response to oncogenic RAS. Proc Natl Acad Sci U S A 2012; 109:13325-30. [PMID: 22847423 DOI: 10.1073/pnas.1120193109] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
RAS is frequently mutated in human cancers and has opposing effects on autophagy and tumorigenesis. Identifying determinants of the cellular responses to RAS is therefore vital in cancer research. Here, we show that autophagic activity dictates the cellular response to oncogenic RAS. N-terminal Apoptosis-stimulating of p53 protein 2 (ASPP2) mediates RAS-induced senescence and inhibits autophagy. Oncogenic RAS-expressing ASPP2((Δ3/Δ3)) mouse embryonic fibroblasts that escape senescence express a high level of ATG5/ATG12. Consistent with the notion that autophagy levels control the cellular response to oncogenic RAS, overexpressing ATG5, but not autophagy-deficient ATG5 mutant K130R, bypasses RAS-induced senescence, whereas ATG5 or ATG3 deficiency predisposes to it. Mechanistically, ASPP2 inhibits RAS-induced autophagy by competing with ATG16 to bind ATG5/ATG12 and preventing ATG16/ATG5/ATG12 formation. Hence, ASPP2 modulates oncogenic RAS-induced autophagic activity to dictate the cellular response to RAS: to proliferate or senesce.
Collapse
|
14
|
Benyamini H, Leonov H, Rotem S, Katz C, Arkin IT, Friedler A. A model for the interaction between NF-kappa-B and ASPP2 suggests an I-kappa-B-like binding mechanism. Proteins 2010; 77:602-11. [PMID: 19507243 DOI: 10.1002/prot.22473] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We used computational methods to study the interaction between two key proteins in apoptosis regulation: the transcription factor NF-kappa-B (NFkappaB) and the proapoptotic protein ASPP2. The C-terminus of ASPP2 contains ankyrin repeats and SH3 domains (ASPP2(ANK-SH3)) that mediate interactions with numerous apoptosis-related proteins, including the p65 subunit of NFkappaB (NFkappaB(p65)). Using peptide-based methods, we have recently identified the interaction sites between NFkappaB(p65) and ASPP2(ANK-SH3) (Rotem et al., J Biol Chem 283, 18990-18999). Here we conducted a computational study of protein docking and molecular dynamics to obtain a structural model of the complex between the full length proteins and propose a mechanism for the interaction. We found that ASPP2(ANK-SH3) binds two sites in NFkappaB(p65), at residues 236-253 and 293-313 that contain the nuclear localization signal (NLS). These sites also mediate the binding of NFkappaB to its natural inhibitor IkappaB, which also contains ankyrin repeats. Alignment of the ankyrin repeats of ASPP2(ANK-SH3) and IkappaB revealed that both proteins share highly similar interfaces at their binding sites to NFkappaB. Protein docking of ASPP2(ANK-SH3) and NFkappaB(p65), as well as molecular dynamics simulations of the proteins, provided structural models of the complex that are energetically similar to the NFkappaB-IkappaB determined structure. Our results show that ASPP2(ANK-SH3) binds NFkappaB(p65) in a similar manner to its natural inhibitor IkappaB, suggesting a possible novel role for ASPP2 as an NFkappaB inhibitor.
Collapse
Affiliation(s)
- Hadar Benyamini
- The Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | | | | | | | | | | |
Collapse
|
15
|
Uhlmann-Schiffler H, Kiermayer S, Stahl H. The DEAD box protein Ddx42p modulates the function of ASPP2, a stimulator of apoptosis. Oncogene 2009; 28:2065-73. [PMID: 19377511 DOI: 10.1038/onc.2009.75] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ddx42p is a recently characterized mammalian DEAD box protein with unknown cellular function. We found that in human cells Ddx42p physically interacts with ASPP2, a major apoptosis inducer known to enhance p53 transactivation of proapoptotic genes. The proteins interact via a domain within the carboxy-terminal part of Ddx42p and a mid-amino-terminal sequence as well as the ankyrin-SH3 region of ASPP2. Overexpression of Ddx42p interferes with apoptosis induction by ASPP2, whereas Ddx42p knockdown reduces the survival rate of cultured human cells. In addition, ASPP2 is found in cytoplasm and nucleus at low Ddx42p level, and predominantly in cytoplasm at high concentration of Ddx42p, respectively. Our results show that Ddx42p is capable of modulating ASPP2 function.
Collapse
Affiliation(s)
- H Uhlmann-Schiffler
- Department of Medical Biochemistry and Molecular Biology, The Saarland University, Homburg, Germany.
| | | | | |
Collapse
|
16
|
Patel S, George R, Autore F, Fraternali F, Ladbury JE, Nikolova PV. Molecular interactions of ASPP1 and ASPP2 with the p53 protein family and the apoptotic promoters PUMA and Bax. Nucleic Acids Res 2008; 36:5139-51. [PMID: 18676979 PMCID: PMC2532732 DOI: 10.1093/nar/gkn490] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The apoptosis stimulating p53 proteins, ASPP1 and ASPP2, are the first two common activators of the p53 protein family that selectively enable the latter to regulate specific apoptotic target genes, which facilitates yes yet unknown mechanisms for discrimination between cell cycle arrest and apoptosis. To better understand the interplay between ASPP- and p53-family of proteins we investigated the molecular interactions between them using biochemical methods and structure-based homology modelling. The data demonstrate that: (i) the binding of ASPP1 and ASPP2 to p53, p63 and p73 is direct; (ii) the C-termini of ASPP1 and ASPP2 interact with the DNA-binding domains of p53 protein family with dissociation constants, Kd, in the lower micro-molar range; (iii) the stoichiometry of binding is 1:1; (iv) the DNA-binding domains of p53 family members are sufficient for these protein–protein interactions; (v) EMSA titrations revealed that while tri-complex formation between ASPPs, p53 family of proteins and PUMA/Bax is mutually exclusive, ASPP2 (but not ASPP1) formed a complex with PUMA (but not Bax) and displaced p53 and p73. The structure-based homology modelling revealed subtle differences between ASPP2 and ASPP1 and together with the experimental data provide novel mechanistic insights.
Collapse
Affiliation(s)
- Seema Patel
- Department of Biochemistry and Pharmaceutical Science Division, School of Biomedical and Health Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford St., London SE1 9NH, UK
| | | | | | | | | | | |
Collapse
|
17
|
Targeted rescue of a destabilized mutant of p53 by an in silico screened drug. Proc Natl Acad Sci U S A 2008; 105:10360-5. [PMID: 18650397 DOI: 10.1073/pnas.0805326105] [Citation(s) in RCA: 283] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The tumor suppressor p53 is mutationally inactivated in approximately 50% of human cancers. Approximately one-third of the mutations lower the melting temperature of the protein, leading to its rapid denaturation. Small molecules that bind to those mutants and stabilize them could be effective anticancer drugs. The mutation Y220C, which occurs in approximately 75,000 new cancer cases per annum, creates a surface cavity that destabilizes the protein by 4 kcal/mol, at a site that is not functional. We have designed a series of binding molecules from an in silico analysis of the crystal structure using virtual screening and rational drug design. One of them, a carbazole derivative (PhiKan083), binds to the cavity with a dissociation constant of approximately 150 muM. It raises the melting temperature of the mutant and slows down its rate of denaturation. We have solved the crystal structure of the protein-PhiKan083 complex at 1.5-A resolution. The structure implicates key interactions between the protein and ligand and conformational changes that occur on binding, which will provide a basis for lead optimization. The Y220C mutant is an excellent "druggable" target for developing and testing novel anticancer drugs based on protein stabilization. We point out some general principles in relationships between binding constants, raising of melting temperatures, and increase of protein half-lives by stabilizing ligands.
Collapse
|
18
|
Rotem S, Katz C, Benyamini H, Lebendiker M, Veprintsev D, Rüdiger S, Danieli T, Friedler A. The structure and interactions of the proline-rich domain of ASPP2. J Biol Chem 2008; 283:18990-9. [PMID: 18448430 DOI: 10.1074/jbc.m708717200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
ASPP2 is a pro-apoptotic protein that stimulates the p53-mediated apoptotic response. The C terminus of ASPP2 contains ankyrin (Ank) repeats and a SH3 domain, which mediate its interactions with numerous partner proteins such as p53, NFkappaB, and Bcl-2. It also contains a proline-rich domain (ASPP2 Pro), whose structure and function are unclear. Here we used biophysical and biochemical methods to study the structure and the interactions of ASPP2 Pro, to gain insight into its biological role. We show, using biophysical and computational methods, that the ASPP2 Pro domain is natively unfolded. We found that the ASPP2 Pro domain interacts with the ASPP2 Ank-SH3 domains, and mapped the interaction sites in both domains. Using a combination of peptide array screening, biophysical and biochemical techniques, we found that ASPP2 Ank-SH3, but not ASPP2 Pro, mediates interactions of ASPP2 with peptides derived from its partner proteins. ASPP2 Pro-Ank-SH3 bound a peptide derived from its partner protein NFkappaB weaker than ASPP2 Ank-SH3 bound this peptide. This suggested that the presence of the proline-rich domain inhibited the interactions mediated by the Ank-SH3 domains. Furthermore, a peptide from ASPP2 Pro competed with a peptide derived from NFkappaB on binding to ASPP2 Ank-SH3. Based on our results, we propose a model in which the interaction between the ASPP2 domains regulates the intermolecular interactions of ASPP2 with its partner proteins.
Collapse
Affiliation(s)
- Shahar Rotem
- Institute of Chemistry, The Hebrew University of Jerusalem, Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Insights into the structure and protein-protein interactions of the pro-apoptotic protein ASPP2. Biochem Soc Trans 2008; 35:966-9. [PMID: 17956256 DOI: 10.1042/bst0350966] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
ASPP (apoptosis-stimulating protein of p53) 2 is a pro-apoptotic protein that stimulates the p53-mediated apoptotic response. Here, we provide an overview of the structure and protein-protein interactions of ASPP2. The C-terminus of ASPP2 contains Ank (ankyrin) repeats and an SH3 domain (Src homology 3 domain). The Ank-SH3 domains mediate interactions between ASPP2 and numerous proteins involved in apoptosis such as p53 and Bcl-2. The proline-rich domain of ASPP2 is unfolded in its native state, but was not shown to mediate intermolecular interactions. Instead, it makes an intramolecular domain-domain interaction with the Ank-SH3 C-terminal domains of ASPP2. This intramolecular interaction between the unstructured proline-rich domain and the structured Ank-SH3 domains in ASPP2, which is possible due to the unfolded nature of the proline-rich domain, is proposed to have an important role in regulating the intermolecular interactions of ASPP2 with its partner proteins.
Collapse
|