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Asare O, Ayala Y, Hafeez BB, Ramirez-Correa GA, Cho YY, Kim DJ. Ultraviolet Radiation Exposure and its Impacts on Cutaneous Phosphorylation Signaling in Carcinogenesis: Focusing on Protein Tyrosine Phosphatases †. Photochem Photobiol 2022; 99:344-355. [PMID: 36029171 DOI: 10.1111/php.13703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/23/2022] [Indexed: 01/14/2023]
Abstract
Sunlight exposure is a significant risk factor for UV-induced deteriorating transformations of epidermal homeostasis leading to skin carcinogenesis. The ability of UVB radiation to cause melanoma, as well as basal and squamous cell carcinomas, makes UVB the most harmful among the three known UV ranges. UVB-induced DNA mutations and dysregulation of signaling pathways contribute to skin cancer formation. Among various signaling pathways modulated by UVB, tyrosine phosphorylation signaling which is mediated by the action of protein tyrosine kinases (PTKs) on specific tyrosine residues is highly implicated in photocarcinogenesis. Following UVB irradiation, PTKs get activated and their downstream signaling pathways contribute to photocarcinogenesis by promoting the survival of damaged keratinocytes and increasing cell proliferation. While UVB activates oncogenic signaling pathways, it can also activate tumor suppressive signaling pathways as initial protective mechanisms to maintain epidermal homeostasis. Tyrosine dephosphorylation is one of the protective mechanisms and is mediated by the action of protein tyrosine phosphatases (PTPs). PTP can counteract UVB-mediated PTK activation and downregulate oncogenic signaling pathways. However, PTPs have not been studied extensively in photocarcinogenesis with previous studies regarding their inactivation induced by UVB. This current review will summarize the recent progress in the protective function of PTPs in epidermal photocarcinogenesis.
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Affiliation(s)
- Obed Asare
- Department of Immunology and Microbiology, School of Medicine, University of Texas Rio Grande Valley, McAllen, TX
| | - Yasmin Ayala
- Department of Immunology and Microbiology, School of Medicine, University of Texas Rio Grande Valley, McAllen, TX
| | - Bilal Bin Hafeez
- Department of Immunology and Microbiology, School of Medicine, University of Texas Rio Grande Valley, McAllen, TX.,South Texas Center for Excellence in Cancer Research, University of Texas Rio Grande Valley, Edinburg, TX
| | - Genaro A Ramirez-Correa
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, McAllen, TX
| | - Yong-Yeon Cho
- College of Pharmacy, The Catholic University of Korea, Bucheon-si, Korea
| | - Dae Joon Kim
- Department of Immunology and Microbiology, School of Medicine, University of Texas Rio Grande Valley, McAllen, TX.,South Texas Center for Excellence in Cancer Research, University of Texas Rio Grande Valley, Edinburg, TX.,Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX
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Kim H, Lee K, Kim JM, Kim MY, Kim JR, Lee HW, Chung YW, Shin HI, Kim T, Park ES, Rho J, Lee SH, Kim N, Lee SY, Choi Y, Jeong D. Selenoprotein W ensures physiological bone remodeling by preventing hyperactivity of osteoclasts. Nat Commun 2021; 12:2258. [PMID: 33859201 PMCID: PMC8050258 DOI: 10.1038/s41467-021-22565-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/18/2021] [Indexed: 11/09/2022] Open
Abstract
Selenoproteins containing selenium in the form of selenocysteine are critical for bone remodeling. However, their underlying mechanism of action is not fully understood. Herein, we report the identification of selenoprotein W (SELENOW) through large-scale mRNA profiling of receptor activator of nuclear factor (NF)-κΒ ligand (RANKL)-induced osteoclast differentiation, as a protein that is downregulated via RANKL/RANK/tumour necrosis factor receptor-associated factor 6/p38 signaling. RNA-sequencing analysis revealed that SELENOW regulates osteoclastogenic genes. SELENOW overexpression enhances osteoclastogenesis in vitro via nuclear translocation of NF-κB and nuclear factor of activated T-cells cytoplasmic 1 mediated by 14-3-3γ, whereas its deficiency suppresses osteoclast formation. SELENOW-deficient and SELENOW-overexpressing mice exhibit high bone mass phenotype and osteoporosis, respectively. Ectopic SELENOW expression stimulates cell-cell fusion critical for osteoclast maturation as well as bone resorption. Thus, RANKL-dependent repression of SELENOW regulates osteoclast differentiation and blocks osteoporosis caused by overactive osteoclasts. These findings demonstrate a biological link between selenium and bone metabolism. Selenoproteins containing selenium have a variety of physiological functions including redox homeostasis and thyroid hormone metabolism. Here, the authors show that RANKL-dependent repression of selenoprotein W regulates cell fusion during osteoclast differentiation and bone remodelling in mice.
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Affiliation(s)
- Hyunsoo Kim
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu, Korea.,Departments of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Kyunghee Lee
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu, Korea
| | - Jin Man Kim
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu, Korea
| | - Mi Yeong Kim
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu, Korea
| | - Jae-Ryong Kim
- Department of Biochemistry and Molecular Biology, Smart-aging Convergence Research Center, Yeungnam University College of Medicine, Daegu, Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Youn Wook Chung
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hong-In Shin
- IHBR, Department of Oral Pathology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Taesoo Kim
- Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon, Korea
| | - Eui-Soon Park
- Department of Microbiology and BK21 Bio Brain Center, Chungnam National University, Daejeon, Korea
| | - Jaerang Rho
- Department of Microbiology and BK21 Bio Brain Center, Chungnam National University, Daejeon, Korea
| | - Seoung Hoon Lee
- Department of Oral Microbiology and Immunology, Wonkwang University School of Dentistry, Iksan, Korea
| | - Nacksung Kim
- National Research Laboratory for Regulation of Bone Metabolism and Disease, Chonnam National University Medical School, Gwangju, Korea
| | - Soo Young Lee
- Division of Life and Pharmaceutical Sciences, Department of Life Science, Center for Cell Signaling & Drug Discovery Research, College of Natural Sciences, Ewha Womans University, Seoul, Korea
| | - Yongwon Choi
- Departments of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Daewon Jeong
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu, Korea.
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Kim M, Morales LD, Lee CJ, Olivarez SA, Kim WJ, Hernandez J, Mummidi S, Jenkinson C, Tsin AT, Jang IS, Slaga TJ, Kim DJ. Overexpression of TC-PTP in murine epidermis attenuates skin tumor formation. Oncogene 2020; 39:4241-4256. [PMID: 32286519 PMCID: PMC7244373 DOI: 10.1038/s41388-020-1282-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 03/18/2020] [Accepted: 03/23/2020] [Indexed: 02/07/2023]
Abstract
T-cell protein tyrosine phosphatase (TC-PTP), encoded by Ptpn2, has been shown to function as a tumor suppressor during skin carcinogenesis. In the current study, we generated a novel epidermal-specific TC-PTP-overexpressing (K5HA.Ptpn2) mouse model to show that TC-PTP contributes to the attenuation of chemically induced skin carcinogenesis through the synergistic regulation of STAT1, STAT3, STAT5, and PI3K/AKT signaling. We found overexpression of TC-PTP increased epidermal sensitivity to DMBA-induced apoptosis and it decreased TPA-mediated hyperproliferation, coinciding with reduced epidermal thickness. Inhibition of STAT1, STAT3, STAT5, or AKT reversed the effects of TC-PTP overexpression on epidermal survival and proliferation. Mice overexpressing TC-PTP in the epidermis developed significantly reduced numbers of tumors during skin carcinogenesis and presented a prolonged latency of tumor initiation. Examination of human papillomas and squamous cell carcinomas (SCCs) revealed that TC-PTP expression was significantly reduced and TC-PTP expression was inversely correlated with the increased grade of SCCs. Our findings demonstrate that TC-PTP is a potential therapeutic target for the prevention of human skin cancer given that it is a major negative regulator of oncogenic signaling.
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Affiliation(s)
- Mihwa Kim
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Liza D Morales
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Cheol Jung Lee
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Serena A Olivarez
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Woo Jin Kim
- School of Mathematical and Statistical Sciences, College of Sciences, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Joselin Hernandez
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Srinivas Mummidi
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Christopher Jenkinson
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Andrew T Tsin
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Ik-Soon Jang
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Daejeon, 305-333, Republic of Korea
| | - Thomas J Slaga
- Department of Pharmacology, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Dae Joon Kim
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.
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Morales LD, Archbold AK, Olivarez S, Slaga TJ, DiGiovanni J, Kim DJ. The role of T-cell protein tyrosine phosphatase in epithelial carcinogenesis. Mol Carcinog 2019; 58:1640-1647. [PMID: 31264291 PMCID: PMC6692238 DOI: 10.1002/mc.23078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 02/06/2023]
Abstract
T-cell protein tyrosine phosphatase (TC-PTP, encoded by PTPN2) is a nonreceptor PTP that is most highly expressed in hematopoietic tissues. TC-PTP modulates a variety of physiological functions including cell cycle progression, cell survival and proliferation, and hematopoiesis through tyrosine dephosphorylation of its target substrates, such as EGFR, JAK1, JAK3, STAT1, and STAT3. Studies with whole or tissue-specific loss of TC-PTP function transgenic mice have shown that TC-PTP has crucial roles in the regulation of the immune response, insulin signaling, and oncogenic signaling. More recently, the generation of epidermal-specific TC-PTP-deficient mice for use in multistage skin carcinogenesis bioassays demonstrated that TC-PTP suppresses skin tumor formation by negatively regulating STAT3 and AKT signaling. Further investigation showed that TC-PTP also minimizes UVB-induced epidermal cell damage by promoting apoptosis through the negative regulation of Flk-1/JNK signaling. These findings provide major evidence for a tumor suppressive function for TC-PTP against environment-induced skin cancer. Here, we will discuss TC-PTP, its substrates, and its functions with an emphasis on its role in skin carcinogenesis.
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Affiliation(s)
- Liza D. Morales
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
- South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
| | - Anna K. Archbold
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
| | - Serena Olivarez
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
| | - Thomas J. Slaga
- Department of Pharmacology, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - John DiGiovanni
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78723, USA
| | - Dae Joon Kim
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
- Department of Molecular Science, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
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Kim M, Morales LD, Kim DJ. TC-PTP nuclear trafficking in keratinocytes. Aging (Albany NY) 2019; 9:2459-2460. [PMID: 29232657 PMCID: PMC5764380 DOI: 10.18632/aging.101345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 12/11/2017] [Indexed: 11/25/2022]
Affiliation(s)
- Mihwa Kim
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
| | - Liza D Morales
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
| | - Dae Joon Kim
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78541, USA
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Ran LW, Wang H, Lan D, Jia HX, Yu SS. Effect of RNA Interference Targeting STAT3 Gene Combined with Ultrasonic Irradiation and SonoVue Microbubbles on Proliferation and Apoptosis in Keratinocytes of Psoriatic Lesions. Chin Med J (Engl) 2018; 131:2097-2104. [PMID: 30127220 PMCID: PMC6111672 DOI: 10.4103/0366-6999.239297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Background Signal transducer and activator of transcription 3 (STAT3) was strongly expressed and activated in psoriatic keratinocytes (KCs) and correlated with the severity of psoriasis. The study aimed to investigate the effects of STAT3 small interfering RNA (siRNA) combined with ultrasonic irradiation and SonoVue microbubbles on the proliferation and apoptosis in KCs of psoriatic lesions and the relative mechanisms. Methods Psoriatic KCs were transfected under four experimental conditions: (1) STAT3 siRNA carried by Lipofectamine 3000 combined with ultrasonic irradiation and SonoVue microbubbles (LUS group); (2) STAT3 siRNA only carried by Lipofectamine 3000 (L group); (3) the negative control of siRNA carried by Lipofectamine 3000 combined with ultrasonic irradiation and SonoVue microbubbles (siRNA-NC); (4) not treated as Blank. Cell Counting Kit-8 assay was used to evaluate the cell proliferation. Cell cycle analysis was detected with cycle test Plus DNA reagent kit associated with flow cytometer. FITC Annexin V apoptosis detection kit associated with flow cytometer was applied for apoptosis analysis. Fluo calcium indicator associated with flow cytometer was used to analyze intracellular free calcium concentration ([Ca2+]i). The expressions of cyclin D1 and Bcl-xL were detected both at the mRNA level by real-time reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level by Western blotting. The obtained data were statistically evaluated by two-way analysis of variance. Results STAT3 siRNA inhibited the growth of KCs in a time-dependent manner showing the highest proliferation inhibition in LUS group with proliferation ratio of 45.38% ± 5.85% at 72h (P < 0.05 vs. L group, siRNA-NC, or Blank). STAT3 siRNA induced an altered cell cycle distribution of KCs showing the highest increases in G2/M-phase population up to 18.06% ± 0.36% in LUS group (P < 0.05 vs. L group, siRNA-NC, or Blank). STAT3 siRNA induced late apoptosis of KCs with the highest late apoptosis percentage of 22.87% ± 1.28% in LUS group (P < 0.05 vs. L group, siRNA-NC, or Blank). STAT3 siRNA induced the elevation of [Ca2+]iof KCs with the highest calcium fluorescence intensity mean of 1213.67 ± 60.51 in LUS group (P < 0.05 vs. L group, siRNA-NC, or Blank). STAT3 siRNA induced the downregulation of cyclin D1 and Bcl-xL expressions of KCs at mRNA and protein levels with the lowest expressions in LUS group with cyclin D1 expression of 51.81% ± 9.58% and 70.17% ± 4.22% at mRNA level and at protein level, respectively, and with Bcl-xL expression of 37.58% ± 4.92% and 64.06% ± 7.78% at mRNA level and at protein level, respectively (P < 0.05 vs. L group, siRNA-NC, or Blank). Conclusions STAT3 siRNA inhibited the growth and induced the apoptosis in psoriatic KCs likely partly through altering cell cycle distribution, elevating [Ca2+]i, and downregulating cyclin D1 and Bcl-xL expressions. Silencing the target gene STAT3 in psoriatic KCs with siRNA combined with ultrasonic irradiation and microbubbles would contribute to a significant innovation as a new clinical therapy for psoriasis.
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Affiliation(s)
- Li-Wei Ran
- Department of Dermatology, Jingxi Campus, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100043, China
| | - Hao Wang
- Department of Dermatology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Dong Lan
- Department of Dermatology, Jingxi Campus, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100043, China
| | - Hong-Xia Jia
- Department of Dermatology, Jingxi Campus, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100043, China
| | - Si-Si Yu
- Department of Dermatology, Jingxi Campus, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100043, China
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Protein Tyrosine Phosphatases as Potential Regulators of STAT3 Signaling. Int J Mol Sci 2018; 19:ijms19092708. [PMID: 30208623 PMCID: PMC6164089 DOI: 10.3390/ijms19092708] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023] Open
Abstract
The signal transducer and activator of transcription 3 (STAT3) protein is a major transcription factor involved in many cellular processes, such as cell growth and proliferation, differentiation, migration, and cell death or cell apoptosis. It is activated in response to a variety of extracellular stimuli including cytokines and growth factors. The aberrant activation of STAT3 contributes to several human diseases, particularly cancer. Consequently, STAT3-mediated signaling continues to be extensively studied in order to identify potential targets for the development of new and more effective clinical therapeutics. STAT3 activation can be regulated, either positively or negatively, by different posttranslational mechanisms including serine or tyrosine phosphorylation/dephosphorylation, acetylation, or demethylation. One of the major mechanisms that negatively regulates STAT3 activation is dephosphorylation of the tyrosine residue essential for its activation by protein tyrosine phosphatases (PTPs). There are seven PTPs that have been shown to dephosphorylate STAT3 and, thereby, regulate STAT3 signaling: PTP receptor-type D (PTPRD), PTP receptor-type T (PTPRT), PTP receptor-type K (PTPRK), Src homology region 2 (SH-2) domain-containing phosphatase 1(SHP1), SH-2 domain-containing phosphatase 2 (SHP2), MEG2/PTP non-receptor type 9 (PTPN9), and T-cell PTP (TC-PTP)/PTP non-receptor type 2 (PTPN2). These regulators have great potential as targets for the development of more effective therapies against human disease, including cancer.
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Baek M, Kim M, Lim JS, Morales LD, Hernandez J, Mummidi S, Williams-Blangero S, Jang IS, Tsin AT, Kim DJ. Epidermal-specific deletion of TC-PTP promotes UVB-induced epidermal cell survival through the regulation of Flk-1/JNK signaling. Cell Death Dis 2018; 9:730. [PMID: 29955047 PMCID: PMC6023867 DOI: 10.1038/s41419-018-0781-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/24/2018] [Accepted: 06/04/2018] [Indexed: 01/27/2023]
Abstract
UVB exposure can contribute to the development of skin cancer by modulating protein tyrosine kinase (PTK) signaling. It has been suggested that UVB radiation increases the ligand-dependent activation of PTKs and induces PTP inactivation. Our recent studies have shown that T-cell protein tyrosine phosphatase (TC-PTP) attenuates skin carcinogenesis induced by chemical regimens, which indicates its critical role in the prevention of skin cancer. In the current work, we report that TC-PTP increases keratinocyte susceptibility to UVB-induced apoptosis via the downregulation of Flk-1/JNK signaling. We showed that loss of TC-PTP led to resistance to UVB-induced apoptosis in vivo epidermis. We established immortalized primary keratinocytes (IPKs) from epidermal-specific TC-PTP-deficient (K14Cre.Ptpn2fl/fl) mice. Immortalized TC-PTP-deficient keratinocytes (TC-PTP/KO IPKs) showed increased cell survival against UVB-induced apoptosis which was concomitant with a UVB-mediated increase in Flk-1 phosphorylation, especially on tyrosine residue 1173. Inhibition of Flk-1 by either its specific inhibitors or siRNA in TC-PTP/KO IPKs reversed this effect and significantly increased cell death after UVB irradiation in comparison with untreated TC-PTP/KO IPKs. Immunoprecipitation analysis using the TC-PTP substrate-trapping mutant TCPTP-D182A indicated that TC-PTP directly interacts with Flk-1 to dephosphorylate it and their interaction was stimulated by UVB. Following UVB-mediated Flk-1 activation, the level of JNK phosphorylation was also significantly increased in TC-PTP/KO IPKs compared to control IPKs. Similar to our results with Flk-1, treatment of TC-PTP/KO IPKs with the JNK inhibitor SP600125 significantly increased apoptosis after UVB irradiation, confirming that the effect of TC-PTP on UVB-mediated apoptosis is regulated by Flk-1/JNK signaling. Western blot analysis showed that both phosphorylated Flk-1 and phosphorylated JNK were significantly increased in the epidermis of TC-PTP-deficient mice compared to control mice following UVB. Our results suggest that TC-PTP plays a protective role against UVB-induced keratinocyte cell damage by promoting apoptosis via negative regulation of Flk-1/JNK survival signaling.
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Affiliation(s)
- Minwoo Baek
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.,College of Pharmacy, University of Minnesota, Duluth, MN, USA
| | - Mihwa Kim
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Jae Sung Lim
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Liza D Morales
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.,South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Joselin Hernandez
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.,South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Srinivas Mummidi
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.,South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Sarah Williams-Blangero
- Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.,South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Ik-Soon Jang
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Daejeon, 305-333, Republic of Korea
| | - Andrew T Tsin
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Dae Joon Kim
- Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA. .,Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA.
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