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Osiriphan M, Insukhin C, Anuchapreeda S, Khamphikham P, Duangmano S. MicroRNA‑223 overexpression suppresses protein kinase C ε expression in human leukemia stem cell‑like KG‑1a cells. Mol Clin Oncol 2024; 21:48. [PMID: 38881704 PMCID: PMC11176719 DOI: 10.3892/mco.2024.2746] [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] [Received: 02/01/2024] [Accepted: 05/01/2024] [Indexed: 06/18/2024] Open
Abstract
MicroRNA-223 (miR-223) is dysregulated in various cancer types, including acute myeloid leukemia (AML). Despite this, there has been a lack of studies exploring the role of miR-223 in leukemic stem cells, particularly those involved in drug resistance, a major cause of chemotherapy failure in AML. The present study aimed to elucidate the impact of miR-223 on drug resistance in the leukemic stem-cell line, KG-1a. Two AML cell lines, KG-1 and KG-1a, differing in the proportion of CD34+CD38- cells, were assessed for doxorubicin (DOX) sensitivity using the Cell Counting Kit-8 assay. The expression levels of miR-223 and protein kinase C ε (PKCε) were evaluated via reverse transcription-quantitative PCR and western blot analysis. The association between miR-223 and its target, PKCε, was confirmed by luciferase activity assay. The effects of miR-223 overexpression and PKCε inhibition were also evaluated in KG-1a cells using miR-223 mimic and small interfering (si)RNA transfection, respectively. Daunorubicin was then used to assess drug sensitivity in the siRNA-transfected KG-1a cells. Compared with KG-1 cells, KG-1a cells displayed greater resistance to DOX, and had increased PKCε levels and decreased miR-223 expression. Overexpression of miR-223 led to PKCε protein downregulation in KG-1a cells, which was further confirmed by a luciferase assay demonstrating miR-223 targeting of PKCε. However, despite these effects, miR-223 overexpression and PKCε inhibition did not change drug sensitivity in KG-1a cells compared with negative control cells. In summary, the present study demonstrated that miR-223 could target and silence PKCε expression in KG-1a cells; however, the chemoresistance of KG-1a cells to anthracycline drugs may not be directly associated with the low expression of miR-223.
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Affiliation(s)
- Mallika Osiriphan
- Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Master's Degree Program in Medical Technology (under the Chiang Mai University Presidential Scholarship), Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
| | - Charapat Insukhin
- Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
| | - Songyot Anuchapreeda
- Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Cancer Research Unit of Associated Medical Sciences, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Hematology and Health Technology Research Center, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
| | - Pinyaphat Khamphikham
- Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Hematology and Health Technology Research Center, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
| | - Suwit Duangmano
- Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Cancer Research Unit of Associated Medical Sciences, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
- Hematology and Health Technology Research Center, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand
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Jin R, Hu W, Zhou M, Lin F, Xu A. Caffeic acid derivative WSY6 protects melanocytes from oxidative stress by reducing ROS production and MAPK activation. Heliyon 2024; 10:e24843. [PMID: 38304822 PMCID: PMC10831733 DOI: 10.1016/j.heliyon.2024.e24843] [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] [Received: 10/12/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/03/2024] Open
Abstract
Purpose Vitiligo is a chronic depigmentation disease caused by a loss of functioning melanocytes and melanin from the epidermis. Oxidative stress-induced damage to melanocytes is key in the pathogenesis of vitiligo. WSY6 is a caffeic acid derivative synthesized from epigallocatechin-3-gallate (EGCG). This study is to investigate whether the new chemical WSY6 protected melanocytes from H2O2-induced cell damage and to elucidate the underlying molecular mechanism. Patients and methods The present study compared the antioxidative potential of WSY6 with EGCG in hydrogen peroxide (H2O2)-treated PIG1 cells. Western blotting was used to study the protein expression of cyto-c, cleaved-caspase3, cleaved-caspase9, and the activation of MAPK family members, including p38, ERK1/2, JNK and their phosphorylation in melanocytes. ROS assay kit to detect intracellular reactive oxygen species production; CCK8 and lactate dehydrogenase leak assay to detect cytotoxicity. Results EGCG and WSY6 ameliorated H2O2-induced oxidative stress damage in PIG1 cells in a does-dependent manner, while WSY6 was much more effective. WSY6 reduced cellular ROS production, cytochrome c release, downregulated caspase-3 and caspase-9 activation. MAPK pathway signaling including phosphorylated p38, ERK and JNK were observed under oxidative stress and can be much protected by pre-treatment of WSY6. Conclusion These results indicated that WSY6 could be a more powerful antioxidant than EGCG and protect melanocytes against oxidative cytotoxicity.
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Affiliation(s)
| | | | - Miaoni Zhou
- Department of Dermatology, Hangzhou Third People's Hospital, Hangzhou, 310009, PR China
| | - Fuquan Lin
- Department of Dermatology, Hangzhou Third People's Hospital, Hangzhou, 310009, PR China
| | - Aie Xu
- Department of Dermatology, Hangzhou Third People's Hospital, Hangzhou, 310009, PR China
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Identifying General Tumor and Specific Lung Cancer Biomarkers by Transcriptomic Analysis. BIOLOGY 2022; 11:biology11071082. [PMID: 36101460 PMCID: PMC9313083 DOI: 10.3390/biology11071082] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/25/2022] [Accepted: 07/03/2022] [Indexed: 11/17/2022]
Abstract
The bioinformatic pipeline previously developed in our research laboratory is used to identify potential general and specific deregulated tumor genes and transcription factors related to the establishment and progression of tumoral diseases, now comparing lung cancer with other two types of cancer. Twenty microarray datasets were selected and analyzed separately to identify hub differentiated expressed genes and compared to identify all the deregulated genes and transcription factors in common between the three types of cancer and those unique to lung cancer. The winning DEGs analysis allowed to identify an important number of TFs deregulated in the majority of microarray datasets, which can become key biomarkers of general tumors and specific to lung cancer. A coexpression network was constructed for every dataset with all deregulated genes associated with lung cancer, according to DAVID’s tool enrichment analysis, and transcription factors capable of regulating them, according to oPOSSUM´s tool. Several genes and transcription factors are coexpressed in the networks, suggesting that they could be related to the establishment or progression of the tumoral pathology in any tissue and specifically in the lung. The comparison of the coexpression networks of lung cancer and other types of cancer allowed the identification of common connectivity patterns with deregulated genes and transcription factors correlated to important tumoral processes and signaling pathways that have not been studied yet to experimentally validate their role in lung cancer. The Kaplan–Meier estimator determined the association of thirteen deregulated top winning transcription factors with the survival of lung cancer patients. The coregulatory analysis identified two top winning transcription factors networks related to the regulatory control of gene expression in lung and breast cancer. Our transcriptomic analysis suggests that cancer has an important coregulatory network of transcription factors related to the acquisition of the hallmarks of cancer. Moreover, lung cancer has a group of genes and transcription factors unique to pulmonary tissue that are coexpressed during tumorigenesis and must be studied experimentally to fully understand their role in the pathogenesis within its very complex transcriptomic scenario. Therefore, the downstream bioinformatic analysis developed was able to identify a coregulatory metafirm of cancer in general and specific to lung cancer taking into account the great heterogeneity of the tumoral process at cellular and population levels.
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Nicholson R, Menezes AC, Azevedo A, Leckenby A, Davies S, Seedhouse C, Gilkes A, Knapper S, Tonks A, Darley RL. Protein Kinase C Epsilon Overexpression Is Associated With Poor Patient Outcomes in AML and Promotes Daunorubicin Resistance Through p-Glycoprotein-Mediated Drug Efflux. Front Oncol 2022; 12:840046. [PMID: 35707351 PMCID: PMC9191576 DOI: 10.3389/fonc.2022.840046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/03/2022] [Indexed: 11/25/2022] Open
Abstract
The protein kinase C (PKC) family of serine/threonine kinases are pleiotropic signaling regulators and are implicated in hematopoietic signaling and development. Only one isoform however, PKCϵ, has oncogenic properties in solid cancers where it is associated with poor outcomes. Here we show that PKCϵ protein is significantly overexpressed in acute myeloid leukemia (AML; 37% of patients). In addition, PKCϵ expression in AML was associated with a significant reduction in complete remission induction and disease-free survival. Examination of the functional consequences of PKCϵ overexpression in normal human hematopoiesis, showed that PKCϵ promotes myeloid differentiation, particularly of the monocytic lineage, and decreased colony formation, suggesting that PKCϵ does not act as an oncogene in hematopoietic cells. Rather, in AML cell lines, PKCϵ overexpression selectively conferred resistance to the chemotherapeutic agent, daunorubicin, by reducing intracellular concentrations of this agent. Mechanistic analysis showed that PKCϵ promoted the expression of the efflux pump, P-GP (ABCB1), and that drug efflux mediated by this transporter fully accounted for the daunorubicin resistance associated with PKCϵ overexpression. Analysis of AML patient samples also showed a link between PKCϵ and P-GP protein expression suggesting that PKCϵ expression drives treatment resistance in AML by upregulating P-GP expression.
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Affiliation(s)
- Rachael Nicholson
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Ana Catarina Menezes
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Aleksandra Azevedo
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Adam Leckenby
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Sara Davies
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Claire Seedhouse
- Academic Haematology, Nottingham University Hospitals and University of Nottingham, Nottingham, United Kingdom
| | - Amanda Gilkes
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
- Cardiff Experimental and Cancer Medicine Centre (ECMC), School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Steve Knapper
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
- Cardiff Experimental and Cancer Medicine Centre (ECMC), School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Alex Tonks
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Richard L. Darley
- Department of Haematology, Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
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Targeting Protein Kinase C for Cancer Therapy. Cancers (Basel) 2022; 14:cancers14051104. [PMID: 35267413 PMCID: PMC8909172 DOI: 10.3390/cancers14051104] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 12/18/2022] Open
Abstract
Simple Summary The protein kinase C (PKC) family belongs to serine-threonine kinases and consists of several subtypes. Increasing evidence suggests that PKCs are critical players in carcinogenesis. Interestingly, PKCs exert both promotive and suppressive effects on tumor cell growth and metastasis, which have attracted immense attention. Herein, we systematically review the current advances in the structure, regulation and biological functions of PKCs, especially the relationship of PKCs with anti-cancer therapy-induced cell death, including the current knowledge of PKCs function in tumor metabolism and microenvironment. Moreover, we discuss the potential role of PKCs as a target for therapeutic intervention in cancer from basic research and clinical trials. Abstract Protein kinase C (PKC) isoforms, a group of serine-threonine kinases, are important regulators in carcinogenesis. Numerous studies have demonstrated that PKC isoforms exert both positive and negative effects on cancer cell demise. In this review, we systematically summarize the current findings on the architecture, activity regulation and biological functions of PKCs, especially their relationship with anti-cancer therapy-induced cell death. Additionally, we elaborate on current knowledge of the effects of PKCs on tumor metabolism and microenvironment, which have gained increasing attention in oncology-related areas. Furthermore, we underscore the basic experimental and clinical implications of PKCs as a target for cancer therapy to evaluate their therapeutic benefits and potential applications.
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The Role of Oxidative Stress in the Pathogenesis of Vitiligo: A Culprit for Melanocyte Death. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:8498472. [PMID: 35103096 PMCID: PMC8800607 DOI: 10.1155/2022/8498472] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/01/2022] [Accepted: 01/03/2022] [Indexed: 12/11/2022]
Abstract
Vitiligo is a common chronic acquired pigmentation disorder characterized by loss of pigmentation. Among various hypotheses proposed for the pathogenesis of vitiligo, oxidative stress-induced immune response that ultimately leads to melanocyte death remains most widely accepted. Oxidative stress which causes elevated levels of reactive oxygen species (ROS) can lead to dysfunction of molecules and organelles, triggering further immune response, and ultimately melanocyte death. In recent years, a variety of cell death modes have been studied, including apoptosis, autophagy and autophagic cell death, ferroptosis, and other novel modes of death, which will be discussed in this review in detail. Oxidative stress is also strongly linked to these modes of death. Under oxidative stress, ROS could induce autophagy by activating the Nrf2 antioxidant pathway of melanocytes. However, persistent stimulation of ROS might eventually lead to excessive activation of Nrf2 antioxidant pathway, which in turn will inactivate autophagy. Moreover, ferroptosis may be triggered by oxidative-related transcriptional production, including ARE, the positive feedback loop related to p62, and the reduced activity and expression of GPX4. Therefore, it is reasonable to infer that these modes of death are involved in the oxidative stress response, and that oxidative stress also acts as an initiator for various modes of death through some complex mechanisms. In this study, we aim to summarize the role of oxidative stress in vitiligo and discuss the corresponding mechanisms of interaction between various modes of cell death and oxidative stress. These findings may provide new ideas for exploring the pathogenesis and potential therapeutic targets of vitiligo.
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Yang D, He Y, Wu B, Liu R, Wang N, Wang T, Luo Y, Li Y, Liu Y. Predictions of the dysregulated competing endogenous RNA signature involved in the progression of human lung adenocarcinoma. Cancer Biomark 2021; 29:399-416. [PMID: 32741804 DOI: 10.3233/cbm-200133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer worldwide. Until now, the molecular mechanisms underlying LUAD progression have not been fully explained. This study aimed to construct a competing endogenous RNA (ceRNA) network to predict the progression in LUAD. METHODS Differentially expressed lncRNAs (DELs), miRNAs (DEMs), and mRNAs (DEGs) were identified from The Cancer Genome Atlas (TCGA) database with a |log2FC|> 1.0 and a false discovery rate (FDR) < 0.05. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction (PPI) network, and survival analyses were performed to analyse these DEGs involved in the ceRNA network. Subsequently, the drug-gene interaction database (DGIdb) was utilized to select candidate LUAD drugs interacting with significant DEGs. Then, lasso-penalized Cox regression and multivariate Cox regression models were used to construct the risk score system. Finally, based on the correlations between DELs and DEGs involved in the risk score system, the final ceRNA network was identified. Meanwhile, the GEPIA2 database and immunohistochemical (IHC) results were utilized to validate the expression levels of selected DEGs. RESULTS A total of 340 DELs, 29 DEMs, and 218 DEGs were selected to construct the initial ceRNA network. Functional enrichment analyses indicated that 218 DEGs were associated with the KEGG pathway terms "microRNAs in cancer", "pathways in cancer", "cell cycle", "HTLV-1 infection", and the "PI3K-Akt signalling pathway". K-M survival analysis of all differentially expressed genes involved in the ceRNA network identified 24 DELs, 4 DEMs, and 29 DEGs, all of which were significantly correlated with LUAD progression (P< 0.05). Furthermore, 15 LUAD drugs interacting with 29 significant DEGs were selected. After lasso-penalized Cox regression and multivariate Cox regression modelling, PRKCE, DLC1, LATS2, and DPY19L1 were incorporated into the risk score system, and the results suggested that LUAD patients who had the high-risk score always suffered from a poorer overall survival. Additionally, the correlation coefficients between these 4 DEGs and their corresponding DELs involved in the ceRNA network suggested that there were 2 significant DEL-DEG pairs, NAV2-AS2 - PRKCE (r= 0.430, P< 0.001) and NAV2-AS2 - LATS2 (r= 0.338, P< 0.001). And NAV2-AS2 - mir-31 - PRKCE and NAV2-SA2 - mir-31 - LATS2 were finally identified as ceRNA network involved in the progression of LUAD. CONCLUSIONS The lncRNA-miRNA-mRNA ceRNA network plays an essential role in predicting the progression of LUAD. These results may improve our understanding and provide novel mechanistic insights to explore prognosis and therapeutic drugs for LUAD patients.
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Affiliation(s)
- Dan Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China.,Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yang He
- Molecular Oncology Laboratory of Cancer Research Institute, The First Affiliated Hospital, China Medical University, Shenyang, Liaoning, China.,Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Bo Wu
- Department of Anus and Intestine Surgery, The First Affiliated Hospital, China Medical University, Shenyang, Liaoning, China
| | - Ruxi Liu
- Department of Rheumatology and Immunology, The First Affiliated Hospital, China Medical University, Shenyang, Liaoning, China
| | - Nan Wang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Tieting Wang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yannan Luo
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yunda Li
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yang Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, China
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Wu X, Yang Y, Xiang L, Zhang C. The fate of melanocyte: Mechanisms of cell death in vitiligo. Pigment Cell Melanoma Res 2020; 34:256-267. [PMID: 33346939 DOI: 10.1111/pcmr.12955] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/10/2020] [Indexed: 01/20/2023]
Abstract
Loss of melanocytes (MCs) is the most notable feature of vitiligo. Hence, it is critical to clarify the mechanisms of MC destruction in vitiligo. Apoptosis is most widely studied cell death pathways in vitiligo. In addition, the other two forms of cell death, conventional necrosis and autophagy seem to be involved in the death of vitiligo MCs under certain situations. Moreover, new types of regulated cell death including necroptosis, pyroptosis, and ferroptosis may also participate in the pathogenesis of vitiligo. Anoikis is likely to be connected with the death of detached MCs, which is provoked specifically by loss of anchorage. Primary phagocytosis, later called phagoptosis can execute death of viable cells, probably partly responsible for the loss of MCs in vitiligo. In this review, we aim to summarize the latest insights into various forms of MC death in vitiligo and discuss the corresponding mechanisms.
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Affiliation(s)
- Xiuyi Wu
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Yiwen Yang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Leihong Xiang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Chengfeng Zhang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
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Yumnam S, Raha S, Kim SM, Venkatarame Gowda Saralamma V, Lee HJ, Ha SE, Heo JD, Lee SJ, Kim EH, Lee WS, Kim JA, Kim GS. Identification of a novel biomarker in tangeretin‑induced cell death in AGS human gastric cancer cells. Oncol Rep 2018; 40:3249-3260. [PMID: 30272339 PMCID: PMC6196609 DOI: 10.3892/or.2018.6730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 09/18/2018] [Indexed: 01/16/2023] Open
Abstract
Proteomic analysis serves as an important biological tool for identifying biological events. Novel biomarkers of a specific disease such as cancer may be identified using these promising techniques. The aim of the present study was to investigate the effect of tangeretin and to identify potential biomarkers in AGS gastric cancer cells using a proteomics approach. The results of the present study revealed that tangeretin inhibited AGS cell viability dose‑dependently with a half‑maximal inhibitory concentration of 100 µM. Two‑dimensional gel electrophoresis was performed to determine the potential biomarker between control and tangeretin (100 µM)‑treated AGS cells. A total of 16 proteins was identified from 36 significant protein spots using matrix‑assisted laser‑desorption/ionization time‑of‑flight‑mass spectrometry using peptide fingerprinting. The bioinformatics tools Protein ANalysis THrough Evolutionary Relationships (PANTHER) and Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to identify the functional properties and association of the proteins obtained. Using western blot analysis, the regulatory pattern of four selected proteins, protein kinase Cε, mitogen‑activated protein kinase 4, phosphoinositide 4‑kinase and poly(ADP‑ribose) polymerase 14, were successfully verified in replicate sample sets. These selected proteins are primarily involved in apoptosis signaling, angiogenesis, cell cycle regulation, receptor kinase binding, intracellular cytoplasmic and nuclear alterations. Therefore, aim of the present study was to identify potential diagnostic biomarkers from the functional categories of altered protein expression in tangeretin‑inhibited AGS gastric cancer cell viability.
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Affiliation(s)
- Silvia Yumnam
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Suchismita Raha
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Seong Min Kim
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Venu Venkatarame Gowda Saralamma
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Ho Jeong Lee
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Sang Eun Ha
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
| | - Jeong Doo Heo
- Gyeongnam Department of Environment Toxicology and Chemistry, Toxicology Screening Research Center, Korea Institute of Toxicology, Jinju, Gyeongsang 52828, Republic of Korea
| | - Sang Joon Lee
- Gyeongnam Department of Environment Toxicology and Chemistry, Toxicology Screening Research Center, Korea Institute of Toxicology, Jinju, Gyeongsang 52828, Republic of Korea
| | - Eun Hee Kim
- Department of Nursing Science, International University of Korea, Jinju, Gyeongsang 52833, Republic of Korea
| | - Won Sup Lee
- Department of Internal Medicine, Institute of Health Sciences, Gyeongsang National University, School of Medicine, Jinju, Gyeongsang 52727, Republic of Korea
| | - Jin A Kim
- Department of Physical Therapy, International University of Korea, Jinju, Gyeongsang 52833, Republic of Korea
| | - Gon Sup Kim
- Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongsang 52828, Republic of Korea
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A photoelectrochemical platform for the capture and release of rare single cells. Nat Commun 2018; 9:2288. [PMID: 29895867 PMCID: PMC5997639 DOI: 10.1038/s41467-018-04701-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 05/18/2018] [Indexed: 01/05/2023] Open
Abstract
For many normal and aberrant cell behaviours, it is important to understand the origin of cellular heterogeneity. Although powerful methods for studying cell heterogeneity have emerged, they are more suitable for common rather than rare cells. Exploring the heterogeneity of rare single cells is challenging because these rare cells must be first pre-concentrated and undergo analysis prior to classification and expansion. Here, a versatile capture & release platform consisting of an antibody-modified and electrochemically cleavable semiconducting silicon surface for release of individual cells of interest is presented. The captured cells can be interrogated microscopically and tested for drug responsiveness prior to release and recovery. The capture & release strategy was applied to identify rare tumour cells from whole blood, monitor the uptake of, and response to, doxorubicin and subsequently select cells for single-cell gene expression based on their response to the doxorubicin. Many cell capture systems exist but the characterisation and controlled release of single cells is a challenge. Here, the authors report on the development of a duel trigger release system using a combination of photo and electro triggers to allow for light based analysis without unwanted release.
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Isakov N. Protein kinase C (PKC) isoforms in cancer, tumor promotion and tumor suppression. Semin Cancer Biol 2017; 48:36-52. [PMID: 28571764 DOI: 10.1016/j.semcancer.2017.04.012] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 04/25/2017] [Indexed: 12/27/2022]
Abstract
The AGC family of serine/threonine kinases (PKA, PKG, PKC) includes more than 60 members that are critical regulators of numerous cellular functions, including cell cycle and differentiation, morphogenesis, and cell survival and death. Mutation and/or dysregulation of AGC kinases can lead to malignant cell transformation and contribute to the pathogenesis of many human diseases. Members of one subgroup of AGC kinases, the protein kinase C (PKC), have been singled out as critical players in carcinogenesis, following their identification as the intracellular receptors of phorbol esters, which exhibit tumor-promoting activities. This observation attracted the attention of researchers worldwide and led to intense investigations on the role of PKC in cell transformation and the potential use of PKC as therapeutic drug targets in cancer diseases. Studies demonstrated that many cancers had altered expression and/or mutation of specific PKC genes. However, the causal relationships between the changes in PKC gene expression and/or mutation and the direct cause of cancer remain elusive. Independent studies in normal cells demonstrated that activation of PKC is essential for the induction of cell activation and proliferation, differentiation, motility, and survival. Based on these observations and the general assumption that PKC isoforms play a positive role in cell transformation and/or cancer progression, many PKC inhibitors have entered clinical trials but the numerous attempts to target PKC in cancer has so far yielded only very limited success. More recent studies demonstrated that PKC function as tumor suppressors, and suggested that future clinical efforts should focus on restoring, rather than inhibiting, PKC activity. The present manuscript provides some historical perspectives on the tumor promoting function of PKC, reviewing some of the observations linking PKC to cancer progression, and discusses the role of PKC in the pathogenesis of cancer diseases and its potential usage as a therapeutic target.
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Affiliation(s)
- Noah Isakov
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
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Nowak G, Takacsova-Bakajsova D, Megyesi J. Deletion of protein kinase C-ε attenuates mitochondrial dysfunction and ameliorates ischemic renal injury. Am J Physiol Renal Physiol 2016; 312:F109-F120. [PMID: 27760765 DOI: 10.1152/ajprenal.00115.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 10/11/2016] [Indexed: 02/08/2023] Open
Abstract
Previously, we documented that activation of protein kinase C-ε (PKC-ε) mediates mitochondrial dysfunction in cultured renal proximal tubule cells (RPTC). This study tested whether deletion of PKC-ε decreases dysfunction of renal cortical mitochondria and improves kidney function after renal ischemia. PKC-ε levels in mitochondria of ischemic kidneys increased 24 h after ischemia. Complex I- and complex II-coupled state 3 respirations were reduced 44 and 27%, respectively, in wild-type (WT) but unchanged and increased in PKC-ε-deficient (KO) mice after ischemia. Respiratory control ratio coupled to glutamate/malate oxidation decreased 50% in WT but not in KO mice. Activities of complexes I, III, and IV were decreased 59, 89, and 61%, respectively, in WT but not in KO ischemic kidneys. Proteomics revealed increases in levels of ATP synthase (α-subunit), complexes I and III, cytochrome oxidase, α-ketoglutarate dehydrogenase, and thioredoxin-dependent peroxide reductase after ischemia in KO but not in WT animals. PKC-ε deletion prevented ischemia-induced increases in oxidant production. Plasma creatinine levels increased 12-fold in WT and 3-fold in KO ischemic mice. PKC-ε deletion reduced tubular necrosis, brush border loss, and distal segment damage in ischemic kidneys. PKC-ε activation in hypoxic RPTC in primary culture exacerbated, whereas PKC-ε inhibition reduced, decreases in: 1) complex I- and complex II-coupled state 3 respirations and 2) activities of complexes I, III, and IV. We conclude that PKC-ε activation mediates 1) dysfunction of complexes I and III of the respiratory chain, 2) oxidant production, 3) morphological damage to the kidney, and 4) decreases in renal functions after ischemia.
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Affiliation(s)
- Grazyna Nowak
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas; and
| | - Diana Takacsova-Bakajsova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas; and
| | - Judit Megyesi
- Division of Nephrology, Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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13
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Long chain n-3 polyunsaturated fatty acids increase the efficacy of docetaxel in mammary cancer cells by downregulating Akt and PKCε/δ-induced ERK pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:380-90. [DOI: 10.1016/j.bbalip.2016.01.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/15/2016] [Accepted: 01/22/2016] [Indexed: 12/21/2022]
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14
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PKCη is an anti-apoptotic kinase that predicts poor prognosis in breast and lung cancer. Biochem Soc Trans 2015; 42:1519-23. [PMID: 25399563 DOI: 10.1042/bst20140182] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The successful treatment of cancer in a disseminated stage using chemotherapy is limited by the occurrence of drug resistance, often mediated by anti-apoptotic mechanisms. Thus the challenge is to pinpoint the underlying key factors and to develop therapies for their direct targeting. Protein kinase C (PKC) enzymes are promising candidates, as some PKCs were shown to be involved in regulation of apoptosis. Our studies and others have shown that PKCη is an anti-apoptotic kinase, able to confer protection on tumour cells against stress and chemotherapy. We have demonstrated that PKCη shuttles between the cytoplasm and the nucleus and that upon DNA damage is tethered at the nuclear membrane. The C1b domain mediates translocation of PKCη to the nuclear envelope and, similar to the full-length protein, could also confer protection against cell death. Furthermore, its localization in cell and nuclear membranes in breast cancer biopsies of neoadjuvant-treated breast cancer patients was an indicator for poor survival and a predictor for the effectiveness of treatment. PKCη is also a novel biomarker for poor prognosis in non-small-cell lung cancer (NSCLC). Thus PKCη presents a potential target for therapy where inhibition of its activity and/or translocation to membranes could interfere with the resistance to chemotherapy.
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15
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Loi TH, Dai P, Carlin S, Melo JV, Ma DDF. Pro-survival role of protein kinase C epsilon in Philadelphia chromosome positive acute leukemia. Leuk Lymphoma 2015; 57:411-418. [DOI: 10.3109/10428194.2015.1043545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Malavez Y, Voss OH, Gonzalez-Mejia ME, Parihar A, Doseff AI. Distinct contribution of protein kinase Cδ and protein kinase Cε in the lifespan and immune response of human blood monocyte subpopulations. Immunology 2015; 144:611-20. [PMID: 25322815 DOI: 10.1111/imm.12412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 02/06/2023] Open
Abstract
Monocytes, key components of the immune system, are a heterogeneous population comprised of classical monocytes (CD16(-) ) and non-classical monocytes (CD16(+) ). Monocytes are short lived and undergo spontaneous apoptosis, unless stimulated. Dysregulation of monocyte numbers contribute to the pathophysiology of inflammatory diseases, yet the contribution of each subset remains poorly characterized. Protein kinase C (PKC) family members are central to monocyte biology; however, their role in regulating lifespan and immune function of CD16(-) and CD16(+) monocytes has not been studied. Here, we evaluated the contribution of PKCδ and PKCε in the lifespan and immune response of both monocyte subsets. We showed that CD16(+) monocytes are more susceptible to spontaneous apoptosis because of the increased caspase-3, -8 and -9 activities accompanied by higher kinase activity of PKCδ. Silencing of PKCδ reduced apoptosis in both CD16(+) and CD16(-) monocytes. CD16(+) monocytes express significantly higher levels of PKCε and produce more tumour necrosis factor-α in CD16(+) compared with CD16(-) monocytes. Silencing of PKCε affected the survival and tumour necrosis factor-α production. These findings demonstrate a complex network with similar topography, yet unique regulatory characteristics controlling lifespan and immune response in each monocyte subset, helping define subset-specific coordination programmes controlling monocyte function.
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Affiliation(s)
- Yadira Malavez
- Department of Molecular Genetics, Department of Internal Medicine, Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
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17
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Mylroie H, Dumont O, Bauer A, Thornton CC, Mackey J, Calay D, Hamdulay SS, Choo JR, Boyle JJ, Samarel AM, Randi AM, Evans PC, Mason JC. PKCε-CREB-Nrf2 signalling induces HO-1 in the vascular endothelium and enhances resistance to inflammation and apoptosis. Cardiovasc Res 2015; 106:509-19. [PMID: 25883219 PMCID: PMC4431664 DOI: 10.1093/cvr/cvv131] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 04/03/2015] [Indexed: 12/25/2022] Open
Abstract
AIMS Vascular injury leading to endothelial dysfunction is a characteristic feature of chronic renal disease, diabetes mellitus, and systemic inflammatory conditions, and predisposes to apoptosis and atherogenesis. Thus, endothelial dysfunction represents a potential therapeutic target for atherosclerosis prevention. The observation that activity of either protein kinase C epsilon (PKCε) or haem oxygenase-1 (HO-1) enhances endothelial cell (EC) resistance to inflammation and apoptosis led us to test the hypothesis that HO-1 is a downstream target of PKCε. METHODS AND RESULTS Expression of constitutively active PKCε in human EC significantly increased HO-1 mRNA and protein, whereas conversely aortas or cardiac EC from PKCε-deficient mice exhibited reduced HO-1 when compared with wild-type littermates. Angiotensin II activated PKCε and induced HO-1 via a PKCε-dependent pathway. PKCε activation significantly attenuated TNFα-induced intercellular adhesion molecule-1, and increased resistance to serum starvation-induced apoptosis. These responses were reversed by the HO antagonist zinc protoporphyrin IX. Phosphokinase antibody array analysis identified CREB1((Ser133)) phosphorylation as a PKCε signalling intermediary, and cAMP response element-binding protein 1 (CREB1) siRNA abrogated PKCε-induced HO-1 up-regulation. Likewise, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was identified as a PKCε target using nuclear translocation and DNA-binding assays, and Nrf2 siRNA prevented PKCε-mediated HO-1 induction. Moreover, depletion of CREB1 inhibited PKCε-induced Nrf2 DNA binding, suggestive of transcriptional co-operation between CREB1 and Nrf2. CONCLUSIONS PKCε activity in the vascular endothelium regulates HO-1 via a pathway requiring CREB1 and Nrf2. Given the potent protective actions of HO-1, we propose that this mechanism is an important contributor to the emerging role of PKCε in the maintenance of endothelial homeostasis and resistance to injury.
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Affiliation(s)
- Hayley Mylroie
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Odile Dumont
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Andrea Bauer
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Clare C Thornton
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - John Mackey
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Damien Calay
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Shahir S Hamdulay
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Joan R Choo
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Joseph J Boyle
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Allen M Samarel
- The Cardiovascular Institute, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Anna M Randi
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Paul C Evans
- Department of Cardiovascular Sciences, University of Sheffield, Sheffield, UK
| | - Justin C Mason
- Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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18
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Pan LL, Wang J, Jia YL, Zheng HM, Wang Y, Zhu YZ. Asymmetric synthesis and evaluation of danshensu-cysteine conjugates as novel potential anti-apoptotic drug candidates. Int J Mol Sci 2014; 16:628-44. [PMID: 25551606 PMCID: PMC4307265 DOI: 10.3390/ijms16010628] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/24/2014] [Indexed: 12/26/2022] Open
Abstract
We have previously reported that the danshensu-cysteine conjugate N-((R)-3-benzylthio-1-methoxy-1-oxo-2-propanyl)-2-acetoxy-3-(3,4-diacetoxyphenyl) propanamide (DSC) is a potent anti-oxidative and anti-apoptotic agent. Herein, we further design and asymmetrically synthesize two diastereoisomers of DSC and explore their potential bioactivities. Our results show that DSC and its two diastereoisomers exert similar protective effects in hydrogen peroxide (H2O2)-induced cellular injury in SH-SY5Y cells, as evidenced by the increase of cell viability, superoxide dismutase (SOD), and reduced glutathione (GSH) activity, and glutathione peroxidase (GPx) expression, and the decrease of cellular morphological changes and nuclear condensation, lactate dehydrogenase (LDH) release, and malondialdehyde (MDA) production. In H2O2-stimulated human umbilical vein endothelial cells (HUVEC), DSC concentration-dependently attenuates H2O2-induced cell death, LDH release, mitochondrial membrane potential collapse, and modulates the expression of apoptosis-related proteins (Bcl-2, Bax, caspase-3, and caspase-9). Our results provide strong evidence that DSC and its two diastereoisomers have similar anti-oxidative activity and that DSC exerts significant vascular-protective effects, at least in part, through inhibition of apoptosis and modulation of endogenous antioxidant enzymes.
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Affiliation(s)
- Li-Long Pan
- Shanghai Key Laboratory of Bioactive Small Molecules, Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Jie Wang
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Yao-Ling Jia
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Hong-Ming Zheng
- Shanghai Key Laboratory of Bioactive Small Molecules, Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Yang Wang
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Yi-Zhun Zhu
- Shanghai Key Laboratory of Bioactive Small Molecules, Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China.
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19
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Pu X, Wang L, Chang JY, Hildebrandt MAT, Ye Y, Lu C, Skinner HD, Niu N, Jenkins GD, Komaki R, Minna JD, Roth JA, Weinshilboum RM, Wu X. Inflammation-related genetic variants predict toxicity following definitive radiotherapy for lung cancer. Clin Pharmacol Ther 2014; 96:609-15. [PMID: 25054431 PMCID: PMC4206576 DOI: 10.1038/clpt.2014.154] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 07/16/2014] [Indexed: 12/25/2022]
Abstract
Definitive radiotherapy improves locoregional control and survival in inoperable non-small cell lung cancer (NSCLC) patients. However, radiation-induced toxicities (pneumonitis/esophagitis) are common dose-limiting inflammatory conditions. We therefore conducted a pathway-based analysis to identify inflammation-related SNPs associated with radiation-induced pneumonitis or esophagitis. 11,930 SNPs were genotyped in 201 stage I-III NSCLC patients treated with definitive radiotherapy. Validation was performed in an additional 220 NSCLC cases. After validation, 19 SNPs remained significant. A polygenic risk score (PRS) was generated to summarize the effect from validated SNPs. Significant improvements in discriminative ability were observed by adding the PRS into the clinical/epidemiological variable-based model. We then used 277 lymphoblastoid cell-lines to assess radiation sensitivity and eQTL relationships of the identified SNPs. Three genes (PRKCE,DDX58 and TNFSF7) were associated with radiation sensitivity. We concluded that inflammation-related genetic variants could contribute to the development of radiation-induced toxicities. These loci could assist in predicting those unfavorable events.
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Affiliation(s)
- X Pu
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - L Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - J Y Chang
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - M A T Hildebrandt
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - Y Ye
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - C Lu
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - H D Skinner
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - N Niu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - G D Jenkins
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | - R Komaki
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - J D Minna
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - J A Roth
- Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - R M Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - X Wu
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
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20
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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: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [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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21
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Othman N, Nagoor NH. The role of microRNAs in the regulation of apoptosis in lung cancer and its application in cancer treatment. BIOMED RESEARCH INTERNATIONAL 2014; 2014:318030. [PMID: 24999473 PMCID: PMC4068038 DOI: 10.1155/2014/318030] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/20/2014] [Indexed: 02/07/2023]
Abstract
Lung cancer remains to be one of the most common and serious types of cancer worldwide. While treatment is available, the survival rate of this cancer is still critically low due to late stage diagnosis and high frequency of drug resistance, thus highlighting the pressing need for a greater understanding of the molecular mechanisms involved in lung carcinogenesis. Studies in the past years have evidenced that microRNAs (miRNAs) are critical players in the regulation of various biological functions, including apoptosis, which is a process frequently evaded in cancer progression. Recently, miRNAs were demonstrated to possess proapoptotic or antiapoptotic abilities through the targeting of oncogenes or tumor suppressor genes. This review examines the involvement of miRNAs in the apoptotic process of lung cancer and will also touch on the promising evidence supporting the role of miRNAs in regulating sensitivity to anticancer treatment.
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Affiliation(s)
- Norahayu Othman
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Noor Hasima Nagoor
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
- Centre for Research in Biotechnology for Agriculture (CEBAR), University of Malaya, 50603 Kuala Lumpur, Malaysia
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22
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Mhaidat NM, Bouklihacene M, Thorne RF. 5-Fluorouracil-induced apoptosis in colorectal cancer cells is caspase-9-dependent and mediated by activation of protein kinase C-δ. Oncol Lett 2014; 8:699-704. [PMID: 25013487 PMCID: PMC4081407 DOI: 10.3892/ol.2014.2211] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 05/13/2014] [Indexed: 02/07/2023] Open
Abstract
Elucidation of the molecular mechanisms by which 5-fluorouracil (5-FU) induces apoptosis is required in order to understand the resistance of colorectal cancer (CRC) cells to 5-FU. In the current study, 5-FU-induced apoptosis was assessed using the propidium iodide method. Involvement of protein kinase C (PKC) was assessed by evaluating the extent of their activation in CRC, following treatment with 5-FU, using biochemical inhibitors and western blot analysis. The results revealed that 5-FU induces varying degrees of apoptosis in CRC cells; HCT116 cells were identified to be the most sensitive cells and SW480 were the least sensitive. In addition, 5-FU-induced apoptosis was caspase-dependent as it appeared to be initiated by caspase-9. Furthermore, PKCɛ was marginally expressed in CRC cells and no changes were observed in the levels of cleavage or phosphorylation following treatment with 5-FU. The treatment of HCT116 cells with 5-FU increased the expression, phosphorylation and cleavage of PKCδ. The inhibition of PKCδ was found to significantly inhibit 5-FU-induced apoptosis. These results indicated that 5-FU induces apoptosis in CRC by the activation of PKCδ and caspase-9. In addition, the levels of PKCδ activation may determine the sensitivity of CRC to 5-FU.
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Affiliation(s)
- Nizar M Mhaidat
- Department of Clinical Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mohammed Bouklihacene
- Department of Clinical Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Rick F Thorne
- Department of Cancer Research Unit, Newcastle University, Newcastle, NSW 2300, Australia
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23
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Abstract
Protein kinase C (PKC) is a family of phospholipid-dependent serine/threonine kinases, which can be further classified into three PKC isozymes subfamilies: conventional or classic, novel or nonclassic, and atypical. PKC isozymes are known to be involved in cell proliferation, survival, invasion, migration, apoptosis, angiogenesis, and drug resistance. Because of their key roles in cell signaling, PKC isozymes also have the potential to be promising therapeutic targets for several diseases, such as cardiovascular diseases, immune and inflammatory diseases, neurological diseases, metabolic disorders, and multiple types of cancer. This review primarily focuses on the activation, mechanism, and function of PKC isozymes during cancer development and progression.
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24
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O'Brian CA, Chu F, Bornmann WG, Maxwell DS. Protein kinase Cα and ε small-molecule targeted therapeutics: a new roadmap to two Holy Grails in drug discovery? Expert Rev Anticancer Ther 2014; 6:175-86. [PMID: 16445370 DOI: 10.1586/14737140.6.2.175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein kinase (PK)Calpha and epsilon are rational targets for cancer therapy. However, targeted experimental therapeutics that inhibit PKCalpha or epsilon are unavailable. The authors established recently that covalent modification of an active-site cysteine in human PKCepsilon, Cys452, by small molecules, for example 2-mercaptoethanolamine, is necessary and sufficient to render PKCepsilon kinase-dead. Cys452 is conserved in only eleven human protein kinase genes, including PKCalpha. Therefore, the design of small molecules that bind PKC active sites with an electrophile substituent positioned proximal to the Cys452 side chain may lead to targeted therapeutics that selectively inhibit PKCepsilon, PKCalpha or other PKC isozymes.
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25
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Targeting PKCε by miR-143 regulates cell apoptosis in lung cancer. FEBS Lett 2013; 587:3661-7. [PMID: 24070896 DOI: 10.1016/j.febslet.2013.09.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 12/30/2022]
Abstract
Non-small cell lung cancer (NSCLC) is one of the most common causes for lung cancer and cancer-related death. The imbalance between cell proliferation and apoptosis was suggested to play an important role in cancer pathogenesis and PKCε is one of the widely recognized targets. Here, we demonstrate that miR-143 is aberrantly downregulated in NSCLC tissue and negatively correlates with expression of PKCε. We show that miR-143 specifically targets the 3'-UTR of PKCε and regulates its expression. Treatment with miR-143 inhibitor mimics cell proliferation and apoptosis imbalance in NSCLC, while inhibition of PKCε can reverse it. Our findings suggest that targeting PKCε overexpression in NSCLC should be beneficial for lung cancer therapy.
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26
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Zhang X, Li D, Li M, Ye M, Ding L, Cai H, Fu D, Lv Z. MicroRNA-146a targets PRKCE to modulate papillary thyroid tumor development. Int J Cancer 2013; 134:257-67. [PMID: 23457043 DOI: 10.1002/ijc.28141] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 02/14/2013] [Indexed: 12/21/2022]
Abstract
MicroRNAs are single-stranded noncoding RNAs composed of approximately 22 nucleotides that suppress gene expression by selectively binding via base-pairing to the complementary 3'-untranslated region (3'-UTR) of messenger RNA transcripts. Protein kinase C epsilon (PKCε) is an important modulating member of the transducing Ras/Raf-1 signal pathway; a computational search revealed miR-146a putatively binds to the 3'-UTR of the PRKCE gene, and thus decreasing PKCε expression. Moreover, PKCε inhibits mitochondrial apoptosis and is associated with the Bcl family. However, it has been previously reported that miR-146a expression in papillary thyroid carcinoma (PTC) is slightly elevated. Thus, we hypothesized that because miR-146a expression depends on nuclear factor kappaB (NF-κB) activation and NF-κB expression is elevated in PTC, miR-146a is potentially upregulated in PTC via negative feedback of NF-κB, and thus suppressing PKCε expression. In our study, we investigated whether overexpression of miR-146a, a tumor-suppressing-miR, in PTC cells decreases cell survival and induces apoptosis. Luciferase reporter assay analysis confirmed the direct binding of miR-146a and PRKCE 3'-UTR. Specific overexpression of exogenous miR-146a significantly decreased PKCε levels in PTC cell line NPA-187 and increased apoptosis. Additionally, using stably expressing miR-146a thyroid carcinoma cells to establish subcutaneous tumors, the tumor growth exhibited significant inhibition. Our study confirmed the tumor-suppressing role of miR-146a in thyroid carcinoma cells and contributes to the knowledge regarding modulation of Ras/Raf-1 signal transduction and apoptosis via PKCε targeted by miR-146a in PTC; moreover, our findings confirmed that miR-146a is involved in the feedback system of the classical NF-κB signal pathway in PTC.
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Affiliation(s)
- Xiaoping Zhang
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China
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Protein kinase C epsilon and genetic networks in osteosarcoma metastasis. Cancers (Basel) 2013; 5:372-403. [PMID: 24216982 PMCID: PMC3730329 DOI: 10.3390/cancers5020372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 03/22/2013] [Accepted: 03/26/2013] [Indexed: 12/20/2022] Open
Abstract
Osteosarcoma (OS) is the most common primary malignant tumor of the bone, and pulmonary metastasis is the most frequent cause of OS mortality. The aim of this study was to discover and characterize genetic networks differentially expressed in metastatic OS. Expression profiling of OS tumors, and subsequent supervised network analysis, was performed to discover genetic networks differentially activated or organized in metastatic OS compared to localized OS. Broad trends among the profiles of metastatic tumors include aberrant activity of intracellular organization and translation networks, as well as disorganization of metabolic networks. The differentially activated PRKCε-RASGRP3-GNB2 network, which interacts with the disorganized DLG2 hub, was also found to be differentially expressed among OS cell lines with differing metastatic capacity in xenograft models. PRKCε transcript was more abundant in some metastatic OS tumors; however the difference was not significant overall. In functional studies, PRKCε was not found to be involved in migration of M132 OS cells, but its protein expression was induced in M112 OS cells following IGF-1 stimulation.
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Liu B, Jian Z, Li Q, Li K, Wang Z, Liu L, Tang L, Yi X, Wang H, Li C, Gao T. Baicalein protects human melanocytes from H₂O₂-induced apoptosis via inhibiting mitochondria-dependent caspase activation and the p38 MAPK pathway. Free Radic Biol Med 2012; 53:183-93. [PMID: 22569306 DOI: 10.1016/j.freeradbiomed.2012.04.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 11/30/2022]
Abstract
The removal of H(2)O(2) by antioxidants has been proven to be beneficial to patients with vitiligo. Baicalein (5,6,7-trihydroxyflavone; BE) has antioxidant activity and has been used in vitiligo therapy in Chinese traditional medicine. In this study, we investigated the potential protective effect and mechanisms of BE against H(2)O(2)-induced apoptosis in human melanocytes. Melanocytes from the PIG1 cell line were pretreated with different concentrations of BE for 1 h, followed by exposure to 1.0 mM H(2)O(2) for 24 h. Cell apoptosis, reactive oxygen species levels, and mitochondrial membrane potentials were evaluated by flow cytometry, and cell viability was determined by an MTT assay. The expressions of Bax, Bcl-2, caspase-3, total and phosphorylated ERKs, and p38 MAPK were assayed by Western blot to investigate the possible molecular mechanisms. Our results showed that BE significantly inhibited H(2)O(2)-induced apoptosis, intracellular reactive oxygen species generation, and changes in the mitochondrial membrane potential. It also reduced the Bax/Bcl-2 ratio, the release of cytochrome c, the activation of caspase-3, and the phosphorylation of p38 MAPK in a concentration-dependent manner. The results demonstrate for the first time that BE exerts a cytoprotective role in H(2)O(2)-induced apoptosis by inhibiting the mitochondria-dependent caspase activation and p38 MAPK pathway.
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Affiliation(s)
- Bangmin Liu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China 710032
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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] [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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Lu N, Wang W, Liu J, Wong CW. Protein kinase C epsilon affects mitochondrial function through estrogen-related receptor alpha. Cell Signal 2011; 23:1473-8. [PMID: 21596133 DOI: 10.1016/j.cellsig.2011.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 04/23/2011] [Accepted: 04/30/2011] [Indexed: 11/27/2022]
Abstract
Members of the protein kinase C (PKC) family have been implicated in controlling cell proliferation, differentiation, and motility. Many of these processes are energy demanding. How PKCs affect mitochondrial function to regulate energy production is not well defined. Using an inhibitor Gö6983 with broad specificity, we found that inhibiting PKCs reduced mitochondrial mass and altered mitochondrial function characterized by elevations in mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) levels. These alterations indicated that Gö6983 suppressed the activities of mitochondrial regulators such as estrogen-related receptor α (ERRα). Indeed, Gö6983 dose-dependently suppressed the expression levels of ERRα-target genes peroxisome proliferator-activated receptor α (PPARα) and medium-chain acyl-CoA dehydrogenase (MCAD). Conversely, PKC activator phorbol ester (PMA) enhanced the expression level of another ERRα-target gene pyruvate dehydrogenase kinase 4 (PDK4). This PMA-mediated induction of PDK4 was blunted by an ERRα inverse agonist XCT-790, suggesting that ERRα plays a role in mediating the effects of PKCs on mitochondrial function. By over-expressing constitutively active forms of PKCs, we found that PKCε preferentially stimulated the transcription activity of ERRα. Through mutating residues on ERRα, we established that this PKCε-induced ERRα activity involves threonine 106, serine 110, and threonine 124 of ERRα. Collectively, these pieces of evidence suggest that ERRα plays an important role down-stream of PKCε to regulate mitochondrial homeostasis.
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Affiliation(s)
- Na Lu
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, 190 Kai Yuan Avenue, Science Park, Guangzhou 510530, China
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31
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Kahana S, Finniss S, Cazacu S, Xiang C, Lee HK, Brodie S, Goldstein RS, Roitman V, Slavin S, Mikkelsen T, Brodie C. Proteasome inhibitors sensitize glioma cells and glioma stem cells to TRAIL-induced apoptosis by PKCε-dependent downregulation of AKT and XIAP expressions. Cell Signal 2011; 23:1348-57. [PMID: 21440622 DOI: 10.1016/j.cellsig.2011.03.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 03/17/2011] [Indexed: 11/17/2022]
Abstract
In this study we examined the effects of proteasome inhibitors on cell apoptosis in TRAIL-resistant glioma cells and glioma stem cells (GSCs). Treatment with proteasome inhibitors and TRAIL induced apoptosis in all the resistant glioma cells and GSCs, but not in astrocytes and neural progenitor cells. Since PKCε has been implicated in the resistance of glioma cells to TRAIL, we examined its role in TRAIL and proteasome inhibitor-induced apoptosis. We found that TRAIL did not induce significant changes in the expression of PKCε, whereas a partial decrease in PKCε expression was obtained by proteasome inhibitors. A combined treatment of TRAIL and proteasome inhibitors induced accumulation of the catalytic fragment of PKCε and significantly and selectively decreased its protein and mRNA levels in the cancer but not in normal cells. Overexpression of PKCε partially inhibited the apoptotic effect of the proteasome inhibitors and TRAIL, and the caspase-resistant PKCεD383A mutant exerted a stronger inhibitory effect. Silencing of PKCε induced cell apoptosis in both glioma cells and GSCs, further supporting its role in cell survival. TRAIL and the proteasome inhibitors decreased the expression of AKT and XIAP in a PKCε-dependent manner and overexpression of these proteins abolished the apoptotic effect of this treatment. Moreover, silencing of XIAP sensitized glioma cells to TRAIL. Our results indicate that proteasome inhibitors sensitize glioma cells and GSCs to TRAIL by decreasing the expression of PKCε, AKT and XIAP. Combining proteasome inhibitors with TRAIL may be useful therapeutically in the treatment of gliomas and the eradication of GSCs.
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Affiliation(s)
- Sarit Kahana
- Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan 52900 (CB), Israel
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Lemjabbar-Alaoui H, Sidhu SS, Mengistab A, Gallup M, Basbaum C. TACE/ADAM-17 phosphorylation by PKC-epsilon mediates premalignant changes in tobacco smoke-exposed lung cells. PLoS One 2011; 6:e17489. [PMID: 21423656 PMCID: PMC3057966 DOI: 10.1371/journal.pone.0017489] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 02/05/2011] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Tobacco smoke predisposes humans and animals to develop lung tumors, but the molecular events responsible for this are poorly understood. We recently showed that signaling mechanisms triggered by smoke in lung cells could lead to the activation of a growth factor signaling pathway, thereby promoting hyperproliferation of lung epithelial cells. Hyperproliferation is considered a premalignant change in the lung, in that increased rates of DNA synthesis are associated with an increased number of DNA copying errors, events that are exacerbated in the presence of tobacco smoke carcinogens. Despite the existence of DNA repair mechanisms, a small percentage of these errors go unrepaired and can lead to tumorigenic mutations. The results of our previous study showed that an early event following smoke exposure was the generation of oxygen radicals through the activation of NADPH oxidase. Although it was clear that these radicals transduced signals through the epidermal growth factor receptor (EGFR), and that this was mediated by TACE-dependent cleavage of amphiregulin, it remained uncertain how oxygen radicals were able to activate TACE. PRINCIPAL FINDINGS In the present study, we demonstrate for the first time that phosphorylation of TACE at serine/threonine residues by tobacco smoke induces amphiregulin release and EGFR activation. TACE phosphorylation is triggered in smoke-exposed lung cells by the ROS-induced activation of PKC through the action of SRC kinase. Furthermore, we identified PKCε as the PKC isoform involved in smoke-induced TACE activation and hyperproliferation of lung cells. CONCLUSIONS Our data elucidate new signaling paradigms by which tobacco smoke promotes TACE activation and hyperproliferation of lung cells.
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Affiliation(s)
- Hassan Lemjabbar-Alaoui
- Thoracic Oncology Laboratory, Department of Surgery, Comprehensive Cancer Center, University of California San Francisco, San Francisco, California, United States of America.
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Totoń E, Ignatowicz E, Skrzeczkowska K, Rybczyńska M. Protein kinase Cε as a cancer marker and target for anticancer therapy. Pharmacol Rep 2011; 63:19-29. [DOI: 10.1016/s1734-1140(11)70395-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/10/2010] [Indexed: 01/23/2023]
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Stewart DJ. Tumor and host factors that may limit efficacy of chemotherapy in non-small cell and small cell lung cancer. Crit Rev Oncol Hematol 2010; 75:173-234. [PMID: 20047843 PMCID: PMC2888634 DOI: 10.1016/j.critrevonc.2009.11.006] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 11/19/2009] [Accepted: 11/27/2009] [Indexed: 12/19/2022] Open
Abstract
While chemotherapy provides useful palliation, advanced lung cancer remains incurable since those tumors that are initially sensitive to therapy rapidly develop acquired resistance. Resistance may arise from impaired drug delivery, extracellular factors, decreased drug uptake into tumor cells, increased drug efflux, drug inactivation by detoxifying factors, decreased drug activation or binding to target, altered target, increased damage repair, tolerance of damage, decreased proapoptotic factors, increased antiapoptotic factors, or altered cell cycling or transcription factors. Factors for which there is now substantial clinical evidence of a link to small cell lung cancer (SCLC) resistance to chemotherapy include MRP (for platinum-based combination chemotherapy) and MDR1/P-gp (for non-platinum agents). SPECT MIBI and Tc-TF scanning appears to predict chemotherapy benefit in SCLC. In non-small cell lung cancer (NSCLC), the strongest clinical evidence is for taxane resistance with elevated expression or mutation of class III beta-tubulin (and possibly alpha tubulin), platinum resistance and expression of ERCC1 or BCRP, gemcitabine resistance and RRM1 expression, and resistance to several agents and COX-2 expression (although COX-2 inhibitors have had minimal impact on drug efficacy clinically). Tumors expressing high BRCA1 may have increased resistance to platinums but increased sensitivity to taxanes. Limited early clinical data suggest that chemotherapy resistance in NSCLC may also be increased with decreased expression of cyclin B1 or of Eg5, or with increased expression of ICAM, matrilysin, osteopontin, DDH, survivin, PCDGF, caveolin-1, p21WAF1/CIP1, or 14-3-3sigma, and that IGF-1R inhibitors may increase efficacy of chemotherapy, particularly in squamous cell carcinomas. Equivocal data (with some positive studies but other negative studies) suggest that NSCLC tumors with some EGFR mutations may have increased sensitivity to chemotherapy, while K-ras mutations and expression of GST-pi, RB or p27kip1 may possibly confer resistance. While limited clinical data suggest that p53 mutations are associated with resistance to platinum-based therapies in NSCLC, data on p53 IHC positivity are equivocal. To date, resistance-modulating strategies have generally not proven clinically useful in lung cancer, although small randomized trials suggest a modest benefit of verapamil and related agents in NSCLC.
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Affiliation(s)
- David J Stewart
- Department of Thoracic/Head & Neck Medical Oncology, MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
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Cheng MB, Zhang Y, Zhong X, Sutter B, Cao CY, Chen XS, Cheng XK, Zhang Y, Xiao L, Shen YF. Stat1 mediates an auto-regulation of hsp90β gene in heat shock response. Cell Signal 2010; 22:1206-13. [DOI: 10.1016/j.cellsig.2010.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 11/30/2022]
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36
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Stewart DJ. Lung Cancer Resistance to Chemotherapy. Lung Cancer 2010. [DOI: 10.1007/978-1-60761-524-8_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Koh W, Sachidanandam K, Stratman AN, Sacharidou A, Mayo AM, Murphy EA, Cheresh DA, Davis GE. Formation of endothelial lumens requires a coordinated PKCepsilon-, Src-, Pak- and Raf-kinase-dependent signaling cascade downstream of Cdc42 activation. J Cell Sci 2009; 122:1812-22. [PMID: 19435802 DOI: 10.1242/jcs.045799] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In this study, we present data showing that Cdc42-dependent lumen formation by endothelial cells (ECs) in three-dimensional (3D) collagen matrices involves coordinated signaling by PKCepsilon in conjunction with the Src-family kinases (SFKs) Src and Yes. Activated SFKs interact with Cdc42 in multiprotein signaling complexes that require PKCepsilon during this process. Src and Yes are differentially expressed during EC lumen formation and siRNA suppression of either kinase, but not Fyn or Lyn, results in significant inhibition of EC lumen formation. Concurrent with Cdc42 activation, PKCepsilon- and SFK-dependent signaling converge to activate p21-activated kinase (Pak)2 and Pak4 in steps that are also required for EC lumen formation. Pak2 and Pak4 further activate two Raf kinases, B-Raf and C-Raf, leading to ERK1 and ERK2 (ERK1/2) activation, which all seem to be necessary for EC lumen formation. This work reveals a multicomponent kinase signaling pathway downstream of integrin-matrix interactions and Cdc42 activation involving PKCepsilon, Src, Yes, Pak2, Pak4, B-Raf, C-Raf and ERK1/2 to control EC lumen formation in 3D collagen matrices.
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Affiliation(s)
- Wonshill Koh
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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Gorin MA, Pan Q. Protein kinase C epsilon: an oncogene and emerging tumor biomarker. Mol Cancer 2009; 8:9. [PMID: 19228372 PMCID: PMC2647895 DOI: 10.1186/1476-4598-8-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 02/19/2009] [Indexed: 12/30/2022] Open
Abstract
Members of the protein kinase C (PKC) family have long been studied for their contributions to oncogenesis. Among the ten different isoforms of this family of serine/threonine kinases, protein kinase Cε (PKCε) is one of the best understood for its role as a transforming oncogene. In vitro, overexpression of PKCε has been demonstrated to increase proliferation, motility, and invasion of fibroblasts or immortalized epithelial cells. In addition, xenograft and transgenic animal models have clearly shown that overexpression of PKCε is tumorigenic resulting in metastatic disease. Perhaps most important in implicating the epsilon isoform in oncogenesis, PKCε has been found to be overexpressed in tumor-derived cell lines and histopathological tumor specimens from various organ sites. Combined, this body of work provides substantial evidence implicating PKCε as a transforming oncogene that plays a crucial role in establishing an aggressive metastatic phenotype. Reviewed here is the literature that has led to the current understanding of PKCε as an oncogene. Moreover, this review focuses on the PKCε-mediated signaling network for cell motility and explores the interaction of PKCε with three major PKCε signaling nodes: RhoA/C, Stat3 and Akt. Lastly, the emerging role of PKCε as a tumor biomarker is discussed.
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Affiliation(s)
- Michael A Gorin
- University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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Caino MC, Meshki J, Kazanietz MG. Hallmarks for senescence in carcinogenesis: novel signaling players. Apoptosis 2009; 14:392-408. [DOI: 10.1007/s10495-009-0316-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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40
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Reyland ME. Protein kinase C isoforms: Multi-functional regulators of cell life and death. Front Biosci (Landmark Ed) 2009; 14:2386-99. [PMID: 19273207 DOI: 10.2741/3385] [Citation(s) in RCA: 207] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The protein kinase C (PKC) family consists of 10 related serine/threonine protein kinases some of which are critical regulators of cell proliferation, survival and cell death. While early studies relied on broad spectrum chemical activators or inhibitors of this family, the generation of isoform specific tools has greatly facilitated our understanding of the contribution of specific PKC isoforms to cell proliferation and apoptosis. These studies suggest that PKC-alpha, PKC-epsilon, and the atypical PKC's, PKC-lambda/iota and PKC-zeta, preferentially function to promote cell proliferation and survival, while the novel isoform, PKC-delta is an important regulator of apoptosis. The essential role of this kinase family in both cell survival and apoptosis suggests that specific isoforms may function as molecular sensors, promoting cell survival or cell death depending on environmental cues. Given their central role in cell and tissue homeostasis, it is not surprising that the expression or activity of some of these kinases is altered in human diseases, particularly cancer.
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Affiliation(s)
- Mary E Reyland
- Department of Craniofacial Biology, University of Colorado Health Sciences Center, Aurora, CO 80045, USA.
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Kvezereli M, Vallentin A, Mochly-Rosen D, Busque S, Fontaine M. Islet Cell Survival During Isolation Improved Through Protein Kinase C Epsilon Activation. Transplant Proc 2008; 40:375-8. [DOI: 10.1016/j.transproceed.2008.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
Protein kinase C (PKC) isozymes catalyze the phosphorylation of substrates that play key roles in the control in proliferation, differentiation, and survival. Treatment of cells with phorbol esters, activators of classical and novel PKC isozymes, leads to a plethora of responses in a strict cell-type-dependent specific manner. Interestingly, a few cell models undergo apoptosis in response to phorbol ester stimulation, including androgen-dependent prostate cancer cells. This effect involves the autocrine secretion of death factors and activation of the extrinsic apoptotic cascade. We have recently found that in other models, such as lung cancer cells, phorbol esters lead to irreversible growth arrest and senescence. This chapter describes the methods we use to assess these phorbol ester responses in cancer cell models, focusing on apoptosis and senescence.
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Felber M, Sonnemann J, Beck JF. Inhibition of novel protein kinase Cɛ augments TRAIL-induced cell death in A549 lung cancer cells. Pathol Oncol Res 2007; 13:295-301. [DOI: 10.1007/bf02940308] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 09/20/2007] [Indexed: 11/29/2022]
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Mhaidat NM, Thorne RF, Zhang XD, Hersey P. Regulation of Docetaxel-Induced Apoptosis of Human Melanoma Cells by Different Isoforms of Protein Kinase C. Mol Cancer Res 2007; 5:1073-81. [DOI: 10.1158/1541-7786.mcr-07-0059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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45
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Podar K, Raab MS, Chauhan D, Anderson KC. The therapeutic role of targeting protein kinase C in solid and hematologic malignancies. Expert Opin Investig Drugs 2007; 16:1693-707. [PMID: 17922632 DOI: 10.1517/13543784.16.10.1693] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The protein kinase C (PKC) family, the most prominent target of tumor-promoting phorbol esters, is functionally linked to cell differentiation, growth, survival, migration and tumorigenesis and so mediates tumor cell proliferation, survival, multidrug resistance, invasion, metastasis and tumor angiogenesis. Therefore, targeting PKC isozymes may represent an attractive target for novel anticancer therapies. Recent preclinical and clinical studies using the macrocyclic bisindolylmaleimide enzastaurin or the N-benzylstaurosporine midostaurin demonstrate promising activity of PKC inhibitors in a variety of tumors, including diffuse large B-cell lymphoma, multiple myeloma and Waldenstroem's macroglobulinemia. However, our knowledge of PKCs in tumorigenesis is still only partial and each PKC isoform may contribute to tumorigenesis in a distinct way. Specifically, PKC isoforms have vastly different roles, which vary depending on expression levels of organ and tissue distribution, cell type, intracellular localization, protein-protein and lipid-protein interactions and the biologic environment. Although PKC activation generally positively affects tumor cell growth, motility, invasion and metastasis, recent reports show that many PKCs can also have negative effects. Therefore, it is necessary to further dissect the relative contribution of PKC isozymes in the development and progression of specific tumors in order to identify therapeutic opportunities, using either PKC inhibitors or PKC activators.
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Affiliation(s)
- Klaus Podar
- Dana-Farber Cancer Institute, Department of Medical Oncology, Jerome Lipper Multiple Myeloma Center, 44 Binney Street, Boston, MA 02115, USA.
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46
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Bae KM, Wang H, Jiang G, Chen MG, Lu L, Xiao L. Protein kinase C epsilon is overexpressed in primary human non-small cell lung cancers and functionally required for proliferation of non-small cell lung cancer cells in a p21/Cip1-dependent manner. Cancer Res 2007; 67:6053-63. [PMID: 17616661 DOI: 10.1158/0008-5472.can-06-4037] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The protein kinase C (PKC) family of proteins plays important roles in growth regulation and is implicated in tumorigenesis. It has become clear that the role of PKC in tumorigenesis is cell context dependent and/or isoform specific. In this study, we showed for the first time by immunohistochemistry that overexpression of PKC epsilon was detected in the vast majority (>90%) of primary human non-small cell lung cancers (NSCLC) compared with normal lung epithelium. Inhibition of the PKC epsilon pathway using a kinase-inactive, dominant-negative PKC epsilon, PKC epsilon(KR), led to a significant inhibition of proliferation and anchorage-independent growth of human NSCLC cells in a p53-independent manner. This was accompanied by a specific induction of the cyclin-dependent kinase (cdk) inhibitor p21/Cip1 but not p27/Kip1. In response to serum stimulation, PKC epsilon(KR)-expressing cells showed a prolonged G(1)-S transition and delayed and reduced activation of cdk2 complexes, which was likely attributed to the increased binding of p21/Cip1 to cdk2. Furthermore, inhibition of PKC epsilon function either by expressing PKC epsilon(KR) or by small interfering RNA (siRNA)-mediated gene knockdown resulted in c-Myc down-regulation, which, in turn, regulated p21/Cip1 expression. Knockdown of PKC epsilon or c-Myc expression using siRNA led to induction of p21/Cip1 and attenuation of G(1)-S transition in NSCLC cells. Using p21(+/+) and p21(-/-) HCT116 isogenic cell lines, we further showed that growth inhibition by PKC epsilon(KR) required the function of p21/Cip1. Collectively, these results reveal an important role for PKC epsilon signaling in lung cancer and suggest that one potential mechanism by which PKC epsilon exerts its oncogenic activity is through deregulation of the cell cycle via a p21/Cip1-dependent mechanism.
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Affiliation(s)
- Kyung-Mi Bae
- University of Florida Shands Cancer Center, University of Florida College of Medicine, Gainesville, Florida 32610-3633, USA
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Xin M, Gao F, May WS, Flagg T, Deng X. Protein Kinase Cζ Abrogates the Proapoptotic Function of Bax through Phosphorylation. J Biol Chem 2007; 282:21268-77. [PMID: 17525161 DOI: 10.1074/jbc.m701613200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase Czeta (PKCzeta) is an atypical PKC isoform that plays an important role in supporting cell survival but the mechanism(s) involved is not fully understood. Bax is a major member of the Bcl-2 family that is required for apoptotic cell death. Because Bax is extensively co-expressed with PKCzeta in both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) cells, it is possible that Bax may act as the downstream target of PKCzeta in regulating survival and chemosensitivity of lung cancer cells. Here we discovered that treatment of cells with nicotine not only enhances PKCzeta activity but also results in Bax phosphorylation and prolonged cell survival, which is suppressed by a PKCzeta specific inhibitor (a myristoylated PKCzeta pseudosubstrate peptide). Purified, active PKCzeta directly phosphorylates Bax in vitro. Overexpression of wild type or the constitutively active A119D but not the dominant negative K281W PKCzeta mutant results in Bax phosphorylation at serine 184. PKCzeta co-localizes and interacts with Bax at the BH3 domain. Specific depletion of PKCzeta by RNA interference blocks nicotine-stimulated Bax phosphorylation and enhances apoptotic cell death. Intriguingly, forced expression of wild type or A119D but not K281W PKCzeta mutant results in accumulation of Bax in cytoplasm and prevents Bax from undergoing a conformational change with prolonged cell survival. Purified PKCzeta can directly dissociate Bax from isolated mitochondria of C2-ceramide-treated cells. Thus, PKCzeta may function as a physiological Bax kinase to directly phosphorylate and interact with Bax, which leads to sequestration of Bax in cytoplasm and abrogation of the proapoptotic function of Bax.
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Affiliation(s)
- Meiguo Xin
- University of Florida Shands Cancer Center, Department of Medicine and Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-3633, USA
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48
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Basu A, Sivaprasad U. Protein kinase Cepsilon makes the life and death decision. Cell Signal 2007; 19:1633-42. [PMID: 17537614 PMCID: PMC1986651 DOI: 10.1016/j.cellsig.2007.04.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 04/23/2007] [Indexed: 12/20/2022]
Abstract
Cancer is caused by dysregulation in cellular signaling systems that control cell proliferation, differentiation and cell death. Protein kinase C (PKC), a family of serine/threonine kinases, plays an important role in the growth factor signal transduction pathway. PKCepsilon, however, is the only PKCepsilon isozyme that has been considered as an oncogene. It can contribute to malignancy by enhancing cell proliferation or by inhibiting cell death. This review focuses on how PKCepsilon collaborates with other signaling pathways, such as Ras/Raf/ERK and Akt, to regulate cell survival and cell death. We have also discussed how PKCepsilon mediates its antiapoptotic signal by altering the level or function of pro- and antiapoptotic Bcl-2 family members.
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Affiliation(s)
- Alakananda Basu
- Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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49
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Abstract
Almost three decades after the discovery of protein kinase C (PKC), we still have only a partial understanding of how this family of serine/threonine kinases is involved in tumour promotion. PKC isozymes - effectors of diacylglycerol (DAG) and the main targets of phorbol-ester tumour promoters - have important roles in cell-cycle regulation, cellular survival, malignant transformation and apoptosis. How do PKC isozymes regulate these diverse cellular processes and what are their contributions to carcinogenesis? Moreover, what is the contribution of all phorbol-ester effectors, which include PKCs and small G-protein regulators? We now face the challenge of dissecting the relative contribution of each DAG signal to cancer progression.
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Affiliation(s)
- Erin M Griner
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics (ITMAT), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA
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50
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Patten SA, Sihra RK, Dhami KS, Coutts CA, Ali DW. Differential expression of PKC isoforms in developing zebrafish. Int J Dev Neurosci 2007; 25:155-64. [PMID: 17403595 DOI: 10.1016/j.ijdevneu.2007.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/21/2007] [Accepted: 02/26/2007] [Indexed: 12/29/2022] Open
Abstract
Protein kinase C isozymes are a biologically diverse group of enzymes known to be involved in a wide variety of cellular processes. They fall into three families (conventional, novel and atypical) depending upon their mode of activation. Several classes of zebrafish neurons have been shown to express PKCalpha during development, but the expression of other isoforms remains unknown. In this study we performed immunohistochemistry to determine if zebrafish express various isoforms of PKC. We used antibodies to test for the presence of enzymes that are thought to be preferentially expressed in the nervous system (PKCgamma, betaII, delta, epsilon, theta and zeta). Here, we show that PKCgamma, epsilon, theta and zeta are expressed in the zebrafish CNS. Anti-PKCgamma labels Rohon-Beard sensory neurons and Mauthner cells. PKCepsilon and zeta staining is widespread in the CNS, and PKCtheta and betaII are expressed in skeletal muscle, especially at intersegmental boundaries. Immunoblot experiments confirm the specificity of the antibodies in zebrafish and indicate that the fish isoforms of PKCgamma, betaII, epsilon and zeta are similar to the mammalian isoforms. Interestingly, PKCtheta appears to be similar to PKCthetaII, which, to date, has been found exclusively in mouse testis, but not in the mammalian CNS. Overall, our findings indicate that several different PKC isoforms are expressed in zebrafish, and that Rohon-Beard, Mauthner cells and muscle fibers preferentially express some isoforms over others.
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Affiliation(s)
- Shunmoogum Aroonassala Patten
- Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton, Alberta T6G 2E9, Canada
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