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Llorens MC, Rossi FA, García IA, Cooke M, Abba MC, Lopez-Haber C, Barrio-Real L, Vaglienti MV, Rossi M, Bocco JL, Kazanietz MG, Soria G. PKCα Modulates Epithelial-to-Mesenchymal Transition and Invasiveness of Breast Cancer Cells Through ZEB1. Front Oncol 2019; 9:1323. [PMID: 31828042 PMCID: PMC6890807 DOI: 10.3389/fonc.2019.01323] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022] Open
Abstract
ZEB1 is a master regulator of the Epithelial-to-Mesenchymal Transition (EMT) program. While extensive evidence confirmed the importance of ZEB1 as an EMT transcription factor that promotes tumor invasiveness and metastasis, little is known about its regulation. In this work, we screened for potential regulatory links between ZEB1 and multiple cellular kinases. Exploratory in silico analysis aided by phospho-substrate antibodies and ZEB1 deletion mutants led us to identify several potential phospho-sites for the family of PKC kinases in the N-terminus of ZEB1. The analysis of breast cancer cell lines panels with different degrees of aggressiveness, together with the evaluation of a battery of kinase inhibitors, allowed us to expose a robust correlation between ZEB1 and PKCα both at mRNA and protein levels. Subsequent validation experiments using siRNAs against PKCα revealed that its knockdown leads to a concomitant decrease in ZEB1 levels, while ZEB1 knockdown had no impact on PKCα levels. Remarkably, PKCα-mediated downregulation of ZEB1 recapitulates the inhibition of mesenchymal phenotypes, including inhibition in cell migration and invasiveness. These findings were extended to an in vivo model, by demonstrating that the stable knockdown of PKCα using lentiviral shRNAs markedly impaired the metastatic potential of MDA-MB-231 breast cancer cells. Taken together, our findings unveil an unforeseen regulatory pathway comprising PKCα and ZEB1 that promotes the activation of the EMT in breast cancer cells.
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Affiliation(s)
- María Candelaria Llorens
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Fabiana Alejandra Rossi
- Instituto de Investigación en Biomedicina de Buenos Aires, IBioBA-CONICET, Partner Institute of the Max Planck Society, Buenos Aires, Argentina
- Translational Medicine Research Institute (IIMT), CONICET, Facultad de Ciencias Biomédicas, Universidad Austral, Buenos Aires, Argentina
| | - Iris Alejandra García
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Martin C. Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas, CONICET, Universidad Nacional de La Plata, La Plata, Argentina
| | - Cynthia Lopez-Haber
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Laura Barrio-Real
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - María Victoria Vaglienti
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mario Rossi
- Instituto de Investigación en Biomedicina de Buenos Aires, IBioBA-CONICET, Partner Institute of the Max Planck Society, Buenos Aires, Argentina
- Translational Medicine Research Institute (IIMT), CONICET, Facultad de Ciencias Biomédicas, Universidad Austral, Buenos Aires, Argentina
| | - José Luis Bocco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marcelo G. Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Gastón Soria
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Cooke M, Zhou X, Casado-Medrano V, Lopez-Haber C, Baker MJ, Garg R, Ann J, Lee J, Blumberg PM, Kazanietz MG. Characterization of AJH-836, a diacylglycerol-lactone with selectivity for novel PKC isozymes. J Biol Chem 2018; 293:8330-8341. [PMID: 29636415 DOI: 10.1074/jbc.ra117.000235] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/08/2018] [Indexed: 11/06/2022] Open
Abstract
Diacylglycerol (DAG) is a key lipid second messenger downstream of cellular receptors that binds to the C1 domain in many regulatory proteins. Protein kinase C (PKC) isoforms constitute the most prominent family of signaling proteins with DAG-responsive C1 domains, but six other families of proteins, including the chimaerins, Ras-guanyl nucleotide-releasing proteins (RasGRPs), and Munc13 isoforms, also play important roles. Their significant involvement in cancer, immunology, and neurobiology has driven intense interest in the C1 domain as a therapeutic target. As with other classes of targets, however, a key issue is the establishment of selectivity. Here, using [3H]phorbol 12,13-dibutyrate ([3H]PDBu) competition binding assays, we found that a synthetic DAG-lactone, AJH-836, preferentially binds to the novel PKC isoforms PKCδ and PKCϵ relative to classical PKCα and PKCβII. Assessment of intracellular translocation, a hallmark for PKC activation, revealed that AJH-836 treatment stimulated a striking preferential redistribution of PKCϵ to the plasma membrane relative to PKCα. Moreover, unlike with the prototypical phorbol ester phorbol 12-myristate 13-acetate (PMA), prolonged exposure of cells to AJH-836 selectively down-regulated PKCδ and PKCϵ without affecting PKCα expression levels. Biologically, AJH-836 induced major changes in cytoskeletal reorganization in lung cancer cells, as determined by the formation of membrane ruffles, via activation of novel PKCs. We conclude that AJH-836 represents a C1 domain ligand with PKC-activating properties distinct from those of natural DAGs and phorbol esters. Our study supports the feasibility of generating selective C1 domain ligands that promote novel biological response patterns.
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Affiliation(s)
- Mariana Cooke
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160
| | - Xiaoling Zhou
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Victoria Casado-Medrano
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160
| | - Cynthia Lopez-Haber
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160
| | - Martin J Baker
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160
| | - Rachana Garg
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160
| | - Jihyae Ann
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Jeewoo Lee
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Marcelo G Kazanietz
- From the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160,
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3
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Bessa C, Soares J, Raimundo L, Loureiro JB, Gomes C, Reis F, Soares ML, Santos D, Dureja C, Chaudhuri SR, Lopez-Haber C, Kazanietz MG, Gonçalves J, Simões MF, Rijo P, Saraiva L. Discovery of a small-molecule protein kinase Cδ-selective activator with promising application in colon cancer therapy. Cell Death Dis 2018; 9:23. [PMID: 29348560 PMCID: PMC5833815 DOI: 10.1038/s41419-017-0154-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 12/12/2022]
Abstract
Protein kinase C (PKC) isozymes play major roles in human diseases, including cancer. Yet, the poor understanding of isozymes-specific functions and the limited availability of selective pharmacological modulators of PKC isozymes have limited the clinical translation of PKC-targeting agents. Here, we report the first small-molecule PKCδ-selective activator, the 7α-acetoxy-6β-benzoyloxy-12-O-benzoylroyleanone (Roy-Bz), which binds to the PKCδ-C1-domain. Roy-Bz potently inhibited the proliferation of colon cancer cells by inducing a PKCδ-dependent mitochondrial apoptotic pathway involving caspase-3 activation. In HCT116 colon cancer cells, Roy-Bz specifically triggered the translocation of PKCδ but not other phorbol ester responsive PKCs. Roy-Bz caused a marked inhibition in migration of HCT116 cells in a PKCδ-dependent manner. Additionally, the impairment of colonosphere growth and formation, associated with depletion of stemness markers, indicate that Roy-Bz also targets drug-resistant cancer stem cells, preventing tumor dissemination and recurrence. Notably, in xenograft mouse models, Roy-Bz showed a PKCδ-dependent antitumor effect, through anti-proliferative, pro-apoptotic, and anti-angiogenic activities. Besides, Roy-Bz was non-genotoxic, and in vivo it had no apparent toxic side effects. Collectively, our findings reveal a novel promising anticancer drug candidate. Most importantly, Roy-Bz opens the way to a new era on PKC biology and pharmacology, contributing to the potential redefinition of the structural requirements of isozyme-selective agents, and to the re-establishment of PKC isozymes as feasible therapeutic targets in human diseases.
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Affiliation(s)
- Cláudia Bessa
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Joana Soares
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Liliana Raimundo
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Joana B Loureiro
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Célia Gomes
- Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, & CNC.IBILI Research Consortium, University of Coimbra, Coimbra, Portugal
| | - Flávio Reis
- Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, & CNC.IBILI Research Consortium, University of Coimbra, Coimbra, Portugal
| | - Miguel L Soares
- Laboratório de Apoio à Investigação em Medicina Molecular, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Daniel Santos
- REQUIMTE, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Chetna Dureja
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India
| | | | - Cynthia Lopez-Haber
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Jorge Gonçalves
- Laboratório de Farmacologia, Departamento de Ciências do Medicamento, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Maria F Simões
- CBIOS-Centro de Investigação em Biociências e Tecnologias da Saúde, Universidade Lusófona, Lisboa, Portugal.,iMed.ULisboa, Instituto de Investigação do Medicamento, Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal
| | - Patrícia Rijo
- CBIOS-Centro de Investigação em Biociências e Tecnologias da Saúde, Universidade Lusófona, Lisboa, Portugal. .,iMed.ULisboa, Instituto de Investigação do Medicamento, Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal.
| | - Lucília Saraiva
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
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Kazanietz MG, Barrio-Real L, Casado-Medrano V, Baker MJ, Lopez-Haber C. The P-Rex1/Rac signaling pathway as a point of convergence for HER/ErbB receptor and GPCR responses. Small GTPases 2016; 9:297-303. [PMID: 27588611 DOI: 10.1080/21541248.2016.1221273] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Guanine nucleotide Exchange Factors (GEFs) are responsible for mediating GDP/GTP exchange for specific small G proteins, such as Rac. There has been substantial evidence for the involvement of Rac-GEFs in the control of cancer cell migration and metastatic progression. We have previously established that the Rac-GEF P-Rex1 is a mediator of actin cytoskeleton rearrangements and cell motility in breast cancer cells downstream of HER/ErbB receptors and the G-Protein Coupled Receptor (GPCR) CXCR4. P-Rex1 is highly expressed in luminal A and B breast cancer compared to normal mammary tissue, whereas expression is very low in basal breast cancer, and its expression correlates with the appearance of metastasis in patients. Here, we discuss the involvement of P-Rex1 as an effector of oncogenic/metastatic receptors in breast cancer and underscore its relevance in the convergence of receptor-triggered motile signals. In addition, we provide an overview of our recent findings describing a cross-talk between HER/ErbB receptors and CXCR4, and how this impacts on the activation of P-Rex1/Rac1 signaling, as well as highlight challenges that lie ahead. We propose a model in which P-Rex1 acts as a crucial node for the integration of upstream inputs from HER/ErbB receptors and CXCR4 in luminal breast cancer cells.
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Affiliation(s)
- Marcelo G Kazanietz
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Laura Barrio-Real
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Victoria Casado-Medrano
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Martin J Baker
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Cynthia Lopez-Haber
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
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Gutierrez-Uzquiza A, Lopez-Haber C, Jernigan DL, Fatatis A, Kazanietz MG. PKCε Is an Essential Mediator of Prostate Cancer Bone Metastasis. Mol Cancer Res 2015; 13:1336-46. [PMID: 26023164 DOI: 10.1158/1541-7786.mcr-15-0111] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/20/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED The bone is a preferred site for metastatic homing of prostate cancer cells. Once prostate cancer patients develop skeletal metastases, they eventually succumb to the disease; therefore, it is imperative to identify key molecular drivers of this process. This study examines the involvement of protein kinase C epsilon (PKCε), an oncogenic protein that is abnormally overexpressed in human tumor specimens and cell lines, on prostate cancer cell bone metastasis. PC3-ML cells, a highly invasive prostate cancer PC3 derivative with bone metastatic colonization properties, failed to induce skeletal metastatic foci upon inoculation into nude mice when PKCε expression was silenced using shRNA. Interestingly, while PKCε depletion had only marginal effects on the proliferative, adhesive, and migratory capacities of PC3-ML cells in vitro or in the growth of xenografts upon s.c. inoculation, it caused a significant reduction in cell invasiveness. Notably, PKCε was required for transendothelial cell migration (TEM) as well as for the growth of PC3-ML cells in a bone biomimetic environment. At a mechanistic level, PKCε depletion abrogates the expression of IL1β, a cytokine implicated in skeletal metastasis. Taken together, PKCε is a key factor for driving the formation of bone metastasis by prostate cancer cells and is a potential therapeutic target for advanced stages of the disease. IMPLICATIONS This study uncovers an important new function of PKCε in the dissemination of cancer cells to the bone; thus, highlighting the promising potential of this oncogenic kinase as a therapeutic target for skeletal metastasis.
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Affiliation(s)
- Alvaro Gutierrez-Uzquiza
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cynthia Lopez-Haber
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Danielle L Jernigan
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Alessandro Fatatis
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania. Program in Biology of Prostate Cancer, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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Wang H, Gutierrez-Uzquiza A, Garg R, Barrio-Real L, Abera MB, Lopez-Haber C, Rosemblit C, Lu H, Abba M, Kazanietz MG. Transcriptional regulation of oncogenic protein kinase Cϵ (PKCϵ) by STAT1 and Sp1 proteins. J Biol Chem 2014; 289:19823-38. [PMID: 24825907 DOI: 10.1074/jbc.m114.548446] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Overexpression of PKCϵ, a kinase associated with tumor aggressiveness and widely implicated in malignant transformation and metastasis, is a hallmark of multiple cancers, including mammary, prostate, and lung cancer. To characterize the mechanisms that control PKCϵ expression and its up-regulation in cancer, we cloned an ∼ 1.6-kb promoter segment of the human PKCϵ gene (PRKCE) that displays elevated transcriptional activity in cancer cells. A comprehensive deletional analysis established two regions rich in Sp1 and STAT1 sites located between -777 and -105 bp (region A) and -921 and -796 bp (region B), respectively, as responsible for the high transcriptional activity observed in cancer cells. A more detailed mutagenesis analysis followed by EMSA and ChIP identified Sp1 sites in positions -668/-659 and -269/-247 as well as STAT1 sites in positions -880/-869 and -793/-782 as the elements responsible for elevated promoter activity in breast cancer cells relative to normal mammary epithelial cells. RNAi silencing of Sp1 and STAT1 in breast cancer cells reduced PKCϵ mRNA and protein expression, as well as PRKCE promoter activity. Moreover, a strong correlation was found between PKCϵ and phospho-Ser-727 (active) STAT1 levels in breast cancer cells. Our results may have significant implications for the development of approaches to target PKCϵ and its effectors in cancer therapeutics.
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Affiliation(s)
- HongBin Wang
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Alvaro Gutierrez-Uzquiza
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Rachana Garg
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Laura Barrio-Real
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Mahlet B Abera
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Cynthia Lopez-Haber
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Cinthia Rosemblit
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Huaisheng Lu
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Martin Abba
- the Centro de Investigaciones Inmunológicas Básicas y Aplicadas, Universidad Nacional de La Plata, CP1900 La Plata, Argentina
| | - Marcelo G Kazanietz
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
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Lopez-Haber C, Kazanietz MG. Cucurbitacin I inhibits Rac1 activation in breast cancer cells by a reactive oxygen species-mediated mechanism and independently of Janus tyrosine kinase 2 and P-Rex1. Mol Pharmacol 2013; 83:1141-54. [PMID: 23478800 DOI: 10.1124/mol.112.084293] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The small GTPase Rac1 has been widely implicated in mammary tumorigenesis and metastasis. Previous studies established that stimulation of ErbB receptors in breast cancer cells activates Rac1 and enhances motility via the Rac-guanine nucleotide exchange factor P-Rex1. As the Janus tyrosine kinase 2 (Jak2)/signal transducer and activator of transcription 3 (Stat3) pathway has been shown to be functionally associated with ErbB receptors, we asked if this pathway could mediate P-Rex1/Rac1 activation in response to ErbB ligands. Here we found that the anticancer agent cucurbitacin I, a Jak2 inhibitor, reduced the activation of Rac1 and motility in response to the ErbB3 ligand heregulin in breast cancer cells. However, Rac1 activation was not affected by Jak2 or Stat3 RNA interference, suggesting that the effect of cucurbitacin I occurs through a Jak2-independent mechanism. Cucurbitacin I also failed to affect the activation of P-Rex1 by heregulin. Subsequent analysis revealed that cucurbitacin I strongly activates RhoA and the Rho effector Rho kinase (ROCK) in breast cancer cells and induces the formation of stress fibers. Interestingly, disruption of the RhoA-ROCK pathway prevented the inhibitory effect of cucurbitacin I on Rac1 activation by heregulin. Lastly, we found that RhoA activation by cucurbitacin I is mediated by reactive oxygen species (ROS). The ROS scavenger N-acetyl L-cysteine and the mitochondrial antioxidant Mito-TEMPO rescued the inhibitory effect of cucurbitacin I on Rac1 activation. In conclusion, these results indicate that ErbB-driven Rac1 activation in breast cancer cells proceeds independently of the Jak2 pathway. Moreover, they established that the inhibitory effect of cucurbitacin I on Rac1 activity involves the alteration of the balance between Rho and Rac.
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Affiliation(s)
- Cynthia Lopez-Haber
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160, USA
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8
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Caino MC, Lopez-Haber C, Kissil JL, Kazanietz MG. Non-small cell lung carcinoma cell motility, rac activation and metastatic dissemination are mediated by protein kinase C epsilon. PLoS One 2012; 7:e31714. [PMID: 22384062 PMCID: PMC3288050 DOI: 10.1371/journal.pone.0031714] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 01/17/2012] [Indexed: 11/18/2022] Open
Abstract
Background Protein kinase C (PKC) ε, a key signaling transducer implicated in mitogenesis, survival, and cancer progression, is overexpressed in human primary non-small cell lung cancer (NSCLC). The role of PKCε in lung cancer metastasis has not yet been established. Principal Findings Here we show that RNAi-mediated knockdown of PKCε in H358, H1299, H322, and A549 NSCLC impairs activation of the small GTPase Rac1 in response to phorbol 12-myristate 13-acetate (PMA), serum, or epidermal growth factor (EGF). PKCε depletion markedly impaired the ability of NSCLC cells to form membrane ruffles and migrate. Similar results were observed by pharmacological inhibition of PKCε with εV1-2, a specific PKCε inhibitor. PKCε was also required for invasiveness of NSCLC cells and modulated the secretion of extracellular matrix proteases and protease inhibitors. Finally, we found that PKCε-depleted NSCLC cells fail to disseminate to lungs in a mouse model of metastasis. Conclusions Our results implicate PKCε as a key mediator of Rac signaling and motility of lung cancer cells, highlighting its potential as a therapeutic target.
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Affiliation(s)
- M Cecilia Caino
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Wertheimer E, Gutierrez-Uzquiza A, Rosemblit C, Lopez-Haber C, Sosa MS, Kazanietz MG. Rac signaling in breast cancer: a tale of GEFs and GAPs. Cell Signal 2012; 24:353-362. [PMID: 21893191 PMCID: PMC3312797 DOI: 10.1016/j.cellsig.2011.08.011] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 08/20/2011] [Indexed: 11/28/2022]
Abstract
Rac GTPases, small G-proteins widely implicated in tumorigenesis and metastasis, transduce signals from tyrosine-kinase, G-protein-coupled receptors (GPCRs), and integrins, and control a number of essential cellular functions including motility, adhesion, and proliferation. Deregulation of Rac signaling in cancer is generally a consequence of enhanced upstream inputs from tyrosine-kinase receptors, PI3K or Guanine nucleotide Exchange Factors (GEFs), or reduced Rac inactivation by GTPase Activating Proteins (GAPs). In breast cancer cells Rac1 is a downstream effector of ErbB receptors and mediates migratory responses by ErbB1/EGFR ligands such as EGF or TGFα and ErbB3 ligands such as heregulins. Recent advances in the field led to the identification of the Rac-GEF P-Rex1 as an essential mediator of Rac1 responses in breast cancer cells. P-Rex1 is activated by the PI3K product PIP3 and Gβγ subunits, and integrates signals from ErbB receptors and GPCRs. Most notably, P-Rex1 is highly overexpressed in human luminal breast tumors, particularly those expressing ErbB2 and estrogen receptor (ER). The P-Rex1/Rac signaling pathway may represent an attractive target for breast cancer therapy.
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Affiliation(s)
- Eva Wertheimer
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Alvaro Gutierrez-Uzquiza
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Cinthia Rosemblit
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Cynthia Lopez-Haber
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Maria Soledad Sosa
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Marcelo G Kazanietz
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
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Caino MC, von Burstin VA, Lopez-Haber C, Kazanietz MG. Differential regulation of gene expression by protein kinase C isozymes as determined by genome-wide expression analysis. J Biol Chem 2011; 286:11254-64. [PMID: 21252239 DOI: 10.1074/jbc.m110.194332] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Protein kinase C (PKC) isozymes are key signal transducers involved in normal physiology and disease and have been widely implicated in cancer progression. Despite our extensive knowledge of the signaling pathways regulated by PKC isozymes and their effectors, there is essentially no information on how individual members of the PKC family regulate gene transcription. Here, we report the first PKC isozyme-specific analysis of global gene expression by microarray using RNAi depletion of diacylglycerol/phorbol ester-regulated PKCs. A thorough analysis of this microarray data revealed unique patterns of gene expression controlled by PKCα, PKCδ, and PKCε, which are remarkably different in cells growing in serum or in response to phorbol ester stimulation. PKCδ is the most relevant isoform in controlling the induction of genes by phorbol ester stimulation, whereas PKCε predominantly regulates gene expression in serum. We also established that two PKCδ-regulated genes, FOSL1 and BCL2A1, mediate the apoptotic effect of phorbol esters or the chemotherapeutic agent etoposide in prostate cancer cells. Our studies offer a unique opportunity for establishing novel transcriptional effectors for PKC isozymes and may have significant functional and therapeutic implications.
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Affiliation(s)
- M Cecilia Caino
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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