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Hu G, Du J, Wang B, Song P, Liu S. Comprehensive analysis of the clinical and prognostic significance of SFRP1 and PRKCB expression in non-small cell lung cancer: a retrospective analysis. Eur J Cancer Prev 2024; 33:45-52. [PMID: 37505453 PMCID: PMC10702695 DOI: 10.1097/cej.0000000000000832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/30/2023] [Indexed: 07/29/2023]
Abstract
OBJECTIVES Secreted frizzled-related protein 1 (SFRP1) and protein kinase C-B (PRKCB) contribute to cancer progression and angiogenesis. This study intended to detect SFRP1 and PRKCB expression in non-small-cell lung cancer (NSCLC) patients and analyze its association with clinicopathological features. METHODS A total of 108 NSCLC patients who underwent surgical resection in our hospital between 2012 and 2017 were retrospectively analyzed. SFRP1 and PRKCB expression was detected using immunohistochemical staining. The relationships between SFRP1 and PRKCB expression and clinicopathological data were analyzed using the chi-square method. Kaplan-Meier analysis was used to investigate survival probability over time. The potential risk of NSCLC morbidity associated with SFRP1 and PRKCB levels was analyzed using univariate and multivariate Cox proportional risk models. RESULTS SFRP1 and PRKCB expression was negative in 114 and 109 of the 180 NSCLC specimens, respectively. SFRP1 expression was significantly associated with TNM stage ( P < 0.001) and tumor diameter ( P < 0.001). PRKCB expression was significantly associated with the TNM stage ( P < 0.001). The correlation between SFRP1 and PRKCB expression was evident ( P = 0.023). SFRP1(-) or PRKCB(-) patients shows lower survival rates than SFRP1(+) or PRKCB(+) patients ( P < 0.001). SFRP1(-)/PRKCB(-) patients had the worst prognosis ( P < 0.001). Furthermore, the mortality of SFRP1(-) or PRKCB(-) patients was significantly higher than that of SFRP1(+) or PRKCB(+). CONCLUSION SFRP1 and PRKCB expression can be used to predict prognosis in patients with NSCLC.
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Affiliation(s)
- GuoQiang Hu
- Department of Respiratory Medicine, Changxing Hospital of Traditional Chinese Medicine, Huzhou
| | - Juan Du
- Department of Respiratory Medicine, Guang’an District People’s Hospital of Guang’an City, Guang’an
| | - Bin Wang
- Department of Respiratory Medicine, Huzhou Hospital, Zhejiang University School of Medicine
- Department of Respiratory Medicine, Huzhou Central Hospital, Huzhou, China
| | - PengTao Song
- Department of Respiratory Medicine, Huzhou Hospital, Zhejiang University School of Medicine
- Department of Respiratory Medicine, Huzhou Central Hospital, Huzhou, China
| | - ShunLin Liu
- Department of Respiratory Medicine, Huzhou Hospital, Zhejiang University School of Medicine
- Department of Respiratory Medicine, Huzhou Central Hospital, Huzhou, China
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Aquino A, Bianchi N, Terrazzan A, Franzese O. Protein Kinase C at the Crossroad of Mutations, Cancer, Targeted Therapy and Immune Response. BIOLOGY 2023; 12:1047. [PMID: 37626933 PMCID: PMC10451643 DOI: 10.3390/biology12081047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
The frequent PKC dysregulations observed in many tumors have made these enzymes natural targets for anticancer applications. Nevertheless, this considerable interest in the development of PKC modulators has not led to the expected therapeutic benefits, likely due to the complex biological activities regulated by PKC isoenzymes, often playing ambiguous and protective functions, further driven by the occurrence of mutations. The structure, regulation and functions of PKCs have been extensively covered in other publications. Herein, we focused on PKC alterations mostly associated with complete functional loss. We also addressed the modest yet encouraging results obtained targeting PKC in selected malignancies and the more frequent negative clinical outcomes. The reported observations advocate the need for more selective molecules and a better understanding of the involved pathways. Furthermore, we underlined the most relevant immune mechanisms controlled by PKC isoforms potentially impacting the immune checkpoint inhibitor blockade-mediated immune recovery. We believe that a comprehensive examination of the molecular features of the tumor microenvironment might improve clinical outcomes by tailoring PKC modulation. This approach can be further supported by the identification of potential response biomarkers, which may indicate patients who may benefit from the manipulation of distinctive PKC isoforms.
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Affiliation(s)
- Angelo Aquino
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy;
| | - Nicoletta Bianchi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (N.B.); (A.T.)
| | - Anna Terrazzan
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (N.B.); (A.T.)
- Laboratory for Advanced Therapy Technologies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Ornella Franzese
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy;
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Activators and Inhibitors of Protein Kinase C (PKC): Their Applications in Clinical Trials. Pharmaceutics 2021; 13:pharmaceutics13111748. [PMID: 34834162 PMCID: PMC8621927 DOI: 10.3390/pharmaceutics13111748] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 02/05/2023] Open
Abstract
Protein kinase C (PKC), a family of phospholipid-dependent serine/threonine kinase, is classed into three subfamilies based on their structural and activation characteristics: conventional or classic PKC isozymes (cPKCs; α, βI, βII, and γ), novel or non-classic PKC isozymes (nPKCs; δ, ε, η, and θ), and atypical PKC isozymes (aPKCs; ζ, ι, and λ). PKC inhibitors and activators are used to understand PKC-mediated intracellular signaling pathways and for the diagnosis and treatment of various PKC-associated diseases, such as cancers, neurological diseases, cardiovascular diseases, and infections. Many clinical trials of PKC inhibitors in cancers showed no significant clinical benefits, meaning that there is a limitation to design a cancer therapeutic strategy targeting PKC alone. This review will focus on the activators and inhibitors of PKC and their applications in clinical trials.
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Ikari A, Fujii N, Hahakabe S, Hayashi H, Yamaguchi M, Yamazaki Y, Endo S, Matsunaga T, Sugatani J. Hyperosmolarity-Induced Down-Regulation of Claudin-2 Mediated by Decrease in PKCβ-Dependent GATA-2 in MDCK Cells. J Cell Physiol 2015; 230:2776-87. [PMID: 25825272 DOI: 10.1002/jcp.25004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 03/25/2015] [Indexed: 01/20/2023]
Abstract
Hyperosmolarity decreases claudin-2 expression in renal tubular epithelial cells, but the molecular mechanism remains undefined. Here, we found that the hyperosmolarity-induced decrease in claudin-2 expression is inhibited by Go6983, a non-selective protein kinase C (PKC) inhibitor, and PKCβ specific inhibitor in Madin-Darby canine kidney II cells. Hyperosmolarity increased intracellular free Ca(2+) concentration and phosphorylated PKCβ level, which were inhibited by RN-1734, an antagonist of transient receptor potential vanilloid 4 channel. Phorbol 12-myristate 13-acetate, a PKC activator, decreased claudin-2 expression. These results indicate hyperosmolarity decreases claudin-2 expression mediated by the activation of RN-1734-sensitive channel and PKCβ. Hyperosmolarity decreased promoter activity of claudin-2, which was inhibited by Go6983 and PKCβ inhibitor similar to those in real-time PCR and Western blotting. The effect of hyperosmolarity on promoter activity was not observed in the construct of -469/-6, a deletion mutant. Claudin-2 has hyperosmolarity-sensitive region in its promoter, which includes GATA binding site. Hyperosmolarity decreased the nuclear level of GATA-2, which was inhibited by Go6983 and PKCβ inhibitor. Mutation of GATA binding site decreased the basal promoter activity and inhibited the effect of hyperosmolarity. In contrast, the hyperosmolarity-induced decrease in reporter activity and claudin-2 expression were rescued by over-expression of wild type GATA-2. Chromatin immunoprecipitation assay showed that GATA-2 bound to promoter region of claudin-2. These results suggest that hyperosmolarity decreases the expression level of claudin-2 via a decrease in PKCβ-dependent GATA-2 transcriptional activity in renal tubular epithelial cells.
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Affiliation(s)
- Akira Ikari
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Naoko Fujii
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Shinya Hahakabe
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Hisayoshi Hayashi
- School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Masahiko Yamaguchi
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yasuhiro Yamazaki
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Satoshi Endo
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Toshiyuki Matsunaga
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Junko Sugatani
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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Huang HL, Wu YC, Su LJ, Huang YJ, Charoenkwan P, Chen WL, Lee HC, Chu WCC, Ho SY. Discovery of prognostic biomarkers for predicting lung cancer metastasis using microarray and survival data. BMC Bioinformatics 2015; 16:54. [PMID: 25881029 PMCID: PMC4349617 DOI: 10.1186/s12859-015-0463-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 01/13/2015] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Few studies have investigated prognostic biomarkers of distant metastases of lung cancer. One of the central difficulties in identifying biomarkers from microarray data is the availability of only a small number of samples, which results overtraining. Recently obtained evidence reveals that epithelial-mesenchymal transition (EMT) of tumor cells causes metastasis, which is detrimental to patients' survival. RESULTS This work proposes a novel optimization approach to discovering EMT-related prognostic biomarkers to predict the distant metastasis of lung cancer using both microarray and survival data. This weighted objective function maximizes both the accuracy of prediction of distant metastasis and the area between the disease-free survival curves of the non-distant and distant metastases. Seventy-eight patients with lung cancer and a follow-up time of 120 months are used to identify a set of gene markers and an independent cohort of 26 patients is used to evaluate the identified biomarkers. The medical records of the 78 patients show a significant difference between the disease-free survival times of the 37 non-distant- and the 41 distant-metastasis patients. The experimental results thus obtained are as follows. 1) The use of disease-free survival curves can compensate for the shortcoming of insufficient samples and greatly increase the test accuracy by 11.10%; and 2) the support vector machine with a set of 17 transcripts, such as CCL16 and CDKN2AIP, can yield a leave-one-out cross-validation accuracy of 93.59%, a test accuracy of 76.92%, a large disease-free survival area of 74.81%, and a mean survival prediction error of 3.99 months. The identified putative biomarkers are examined using related studies and signaling pathways to reveal the potential effectiveness of the biomarkers in prospective confirmatory studies. CONCLUSIONS The proposed new optimization approach to identifying prognostic biomarkers by combining multiple sources of data (microarray and survival) can facilitate the accurate selection of biomarkers that are most relevant to the disease while solving the problem of insufficient samples.
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Affiliation(s)
- Hui-Ling Huang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan. .,Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
| | - Yu-Chung Wu
- Division of Thoracic Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.
| | - Li-Jen Su
- Institute of Systems Biology and Bioinformatics, National Central University, Taoyuan, Taiwan.
| | - Yun-Ju Huang
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan.
| | - Phasit Charoenkwan
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan.
| | - Wen-Liang Chen
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
| | - Hua-Chin Lee
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan. .,Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
| | | | - Shinn-Ying Ho
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan. .,Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
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Zhang LL, Cao FF, Wang Y, Meng FL, Zhang Y, Zhong DS, Zhou QH. The protein kinase C (PKC) inhibitors combined with chemotherapy in the treatment of advanced non-small cell lung cancer: meta-analysis of randomized controlled trials. Clin Transl Oncol 2014; 17:371-7. [PMID: 25351171 DOI: 10.1007/s12094-014-1241-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 10/01/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND The application of newer signaling pathway-targeted agents has become an important addition to chemotherapy in the treatment of advanced non-small cell lung cancer (NSCLC). In this study, we evaluated the efficacy and toxicities of PKC inhibitors combined with chemotherapy versus chemotherapy alone for patients with advanced NSCLC systematically. PATIENTS AND MATERIALS Literature retrieval, trials selection and assessment, data collection, and statistic analysis were performed according to the Cochrane Handbook 5.1.0. The outcome measures were tumor response rate, disease control rate, progression-free survival (PFS), overall survival (OS), and adverse effects. RESULTS Five randomized controlled trials, comprising totally 1,005 patients, were included in this study. Meta-analysis showed significantly decreased response rate (RR 0.79; 95 % CI 0.64-0.99) and disease control rate (RR 0.90; 95 % CI 0.82-0.99) in PKC inhibitors-chemotherapy groups versus chemotherapy groups. There was no significant difference between the two treatment groups regarding progression-free survival (PFS, HR 1.05; 95 % CI 0.91-1.22) and overall survival (OS, HR 1.00; 95 % CI 0.86-1.16). The risk of grade 3/4 neutropenia, leucopenia, and thrombosis/embolism increased significantly in PKC inhibitors combination groups as compared with chemotherapy alone groups. CONCLUSION The use of PKC inhibitors in addition to chemotherapy was not a valid alternative for patients with advanced NSCLC.
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Affiliation(s)
- L L Zhang
- Department of Oncology, Tianjin Medical University General Hospital, #154 Anshan Road, Heping District, Tianjin, 300052, China,
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Transcriptional analysis of apoptotic cerebellar granule neurons following rescue by gastric inhibitory polypeptide. Int J Mol Sci 2014; 15:5596-622. [PMID: 24694544 PMCID: PMC4013584 DOI: 10.3390/ijms15045596] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/04/2014] [Accepted: 03/17/2014] [Indexed: 12/31/2022] Open
Abstract
Apoptosis triggered by exogenous or endogenous stimuli is a crucial phenomenon to determine the fate of neurons, both in physiological and in pathological conditions. Our previous study established that gastric inhibitory polypeptide (Gip) is a neurotrophic factor capable of preventing apoptosis of cerebellar granule neurons (CGNs), during its pre-commitment phase. In the present study, we conducted whole-genome expression profiling to obtain a comprehensive view of the transcriptional program underlying the rescue effect of Gip in CGNs. By using DNA microarray technology, we identified 65 genes, we named survival related genes, whose expression is significantly de-regulated following Gip treatment. The expression levels of six transcripts were confirmed by real-time quantitative polymerase chain reaction. The proteins encoded by the survival related genes are functionally grouped in the following categories: signal transduction, transcription, cell cycle, chromatin remodeling, cell death, antioxidant activity, ubiquitination, metabolism and cytoskeletal organization. Our data outline that Gip supports CGNs rescue via a molecular framework, orchestrated by a wide spectrum of gene actors, which propagate survival signals and support neuronal viability.
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Szabo E, Mao JT, Lam S, Reid ME, Keith RL. Chemoprevention of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2013; 143:e40S-e60S. [PMID: 23649449 PMCID: PMC3749715 DOI: 10.1378/chest.12-2348] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/30/2012] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Lung cancer is the most common cause of cancer death in men and women in the United States. Cigarette smoking is the main risk factor. Former smokers are at a substantially increased risk of developing lung cancer compared with lifetime never smokers. Chemoprevention refers to the use of specific agents to reverse, suppress, or prevent the process of carcinogenesis. This article reviews the major agents that have been studied for chemoprevention. METHODS Articles of primary, secondary, and tertiary prevention trials were reviewed and summarized to obtain recommendations. RESULTS None of the phase 3 trials with the agents β-carotene, retinol, 13-cis-retinoic acid, α-tocopherol, N-acetylcysteine, acetylsalicylic acid, or selenium has demonstrated beneficial and reproducible results. To facilitate the evaluation of promising agents and to lessen the need for a large sample size, extensive time commitment, and expense, surrogate end point biomarker trials are being conducted to assist in identifying the most promising agents for later-stage chemoprevention trials. With the understanding of important cellular signaling pathways and the expansion of potentially important targets, agents (many of which target inflammation and the arachidonic acid pathway) are being developed and tested which may prevent or reverse lung carcinogenesis. CONCLUSIONS By integrating biologic knowledge, additional early-phase trials can be performed in a reasonable time frame. The future of lung cancer chemoprevention should entail the evaluation of single agents or combinations that target various pathways while working toward identification and validation of intermediate end points.
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Affiliation(s)
- Eva Szabo
- Lung and Upper Aerodigestive Cancer Research Group, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Jenny T Mao
- Division of Pulmonary, Critical Care, and Sleep Medicine, New Mexico VA Health Care System/University of New Mexico, Albuquerque, NM
| | - Stephen Lam
- British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Mary E Reid
- Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY
| | - Robert L Keith
- VA Eastern Colorado Health Care System, University of Colorado School of Medicine, Denver, CO.
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Lee AY, Noh M. The regulation of epidermal melanogenesis via cAMP and/or PKC signaling pathways: insights for the development of hypopigmenting agents. Arch Pharm Res 2013; 36:792-801. [PMID: 23604723 DOI: 10.1007/s12272-013-0130-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/13/2013] [Indexed: 12/21/2022]
Abstract
Abnormal pigmentation, particularly hyperpigmentation, is major issue of concern for people with colored skin. Several hypopigmenting agents, which exert their action by inhibiting tyrosinase activity and/or transcription, have been used for treatment. However, results have been discouraging. To manage abnormal pigmentation properly, the mechanisms of melanogenesis should be understood. Endogenous and exogenous factors affect melanogenesis via intracellular machineries. cAMP and PKC are critical factors of important transduction pathways and cross-talk between them could amplify the melanogenic effect. Here, factors involved in melanogenesis regulation via cAMP and/or PKC pathways are reviewed with their action mechanisms.
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Affiliation(s)
- Ai-Young Lee
- Department of Dermatology, Dongguk University Seoul, Graduate School of Medicine, 814 Siksa-dong, Ilsandong-gu, Goyang-si, Gyeonggi-do, 410-773, South Korea.
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A phase II study of enzastaurin in combination with erlotinib in patients with previously treated advanced non-small cell lung cancer. Lung Cancer 2012; 78:57-62. [DOI: 10.1016/j.lungcan.2012.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/31/2012] [Accepted: 06/06/2012] [Indexed: 01/24/2023]
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Abstract
Background: Previously, using gene-knockdown techniques together with genome expression array analysis, we showed the gene protein Kinase C (PKC)-zeta (PRKCZ) to mediate the malignant phenotype of human prostate cancer. However, according to NCBI, the gene has undergone several major iterations. Therefore, to understand the relationship between its structure and biological activities, we have analysed its expressed sequence in prostate cancer cell lines and tissues. Methods: Transcriptome-walking and targeted PCR were used to sequence the mRNA transcribed from PRKCZ. Hydropathy analysis was employed to analyse the hypothetical protein sequence subsequently translated and to identify an appropriate epitope to generate a specific monoclonal antibody. Results: A novel sequence was identified within the 3′-terminal domain of human PRKCZ that, in prostate cancer cell lines and tissues, is expressed during transcription and thereafter translated into protein (designated PKC-ζ-PrC) independent of conventional PKC-ζ-a. The monoclonal antibody detected expression of this 96 kD protein only within malignant prostatic epithelium. Interpretation: Transcription and translation of this gene sequence, including previous intronic sequences, generates a novel specific biomarker of human prostate cancer. The presence of catalytic domains characteristic of classic PKC-β and atypical PKC-ι within PKC-ζ-PrC provides a potential mechanism for this PRKCZ variant to modulate the malignant prostatic phenotype out-with normal cell-regulatory control.
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Chen X, Zhang X, Jia C, Xu J, Gao H, Zhang G, Du X, Zhang H. Membrane depolarization increases membrane PtdIns(4,5)P2 levels through mechanisms involving PKC βII and PI4 kinase. J Biol Chem 2011; 286:39760-7. [PMID: 21953466 DOI: 10.1074/jbc.m111.289090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In a previous study, we showed that membrane depolarization induced elevation of membrane phosphatidylinositol 4,5-bisphosphates (PtdIns(4,5)P(2), also known as PIP(2)) and subsequently increased the KCNQ2/Q3 currents expressed in Xenopus oocytes through increased PI4 kinase activity. In this study, the underlying mechanism for this depolarization-induced enhancement of PIP(2) synthesis was further investigated. Our results indicate that activation of protein kinase C (PKC) isozyme βII was responsible for the enhanced PIP(2) synthesis. We found that phorbol-12-myristate, 13-acetate (PMA), an activator of PKC, mimicked the effects of the membrane depolarization by increasing KCNQ2/Q3 activity, elevating membrane PIP(2) levels and increasing activity of PI4 kinase β. Furthermore, membrane depolarization enhanced PKC activity. The effects of both depolarization and PMA were blocked by a PKC inhibitor or PI4 kinase β RNA interference. Further results demonstrate that the depolarization selectively activated the PKC βII isoform and enhanced its interaction with PI4 kinase β. These results reveal that the depolarization-induced elevation of membrane PIP(2) is through activation of PKC and the subsequent increased activity of PI4 kinase β.
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Affiliation(s)
- Xingjuan Chen
- Key Laboratory of Neural and Vascular Biology, Ministry of Education, Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
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