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Sun T, Zhang K, Li W, Liu Y, Pangeni RP, Li A, Arvanitis L, Raz DJ. Transcription factor AP2 enhances malignancy of non-small cell lung cancer through upregulation of USP22 gene expression. Cell Commun Signal 2022; 20:147. [PMID: 36123698 PMCID: PMC9484186 DOI: 10.1186/s12964-022-00946-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 07/23/2022] [Indexed: 11/10/2022] [Imported: 08/29/2023] Open
Abstract
BACKGROUND Ubiquitin-specific protease 22 (USP22), a putative cancer stem cell marker, is frequently upregulated in cancers, and USP22 overexpression is associated with aggressive growth, metastasis, and therapy resistance in various human cancers including lung cancer. However, USP22 gene amplification seldom occurs, and the mechanism underlying USP22 upregulation in human cancers remains largely unknown. METHODS A luciferase reporter driven by a promoter region of USP22 gene was selectively constructed to screen against a customized siRNA library targeting 89 selected transcription factors to identify potential transcription factors (TFs) that regulate USP22 expression in human non-small cell lung cancers (NSCLC). Association of identified TFs with USP22 and potential role of the TFs were validated and explored in NSCLC by biological assays and immunohistochemistry analysis. RESULTS Luciferase reporter assays revealed that SP1 and activating transcription factor 3 (ATF3) inhibit USP22 transcription, while transcription factor AP-2 Alpha/Beta (TFAP2A/2B) and c-Myc promote USP22 transcription. Binding site-directed mutagenesis and chromosome immunoprecipitation (ChIP) assays validated AP2α and AP2β are novel TFs of USP22. Furthermore, overexpression of AP2A and AP2B significantly upregulates USP22 expression, and its target: Cyclin D1, concurrently enhances the proliferation, migration, and invasion of NSCLC A549 and H1299 cells in a partially USP22-dependent manner. Moreover, AP2 protein level correlated with USP22 protein in human NSCLC tissues. CONCLUSION Our findings indicate AP2α and AP2β are important transcription factors driving USP22 gene expression to promote the progression of NSCLC, and further support USP22 as a potential biomarker and therapeutic target for lung cancer. Video Abstract.
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Affiliation(s)
- Ting Sun
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, CA, USA.,Laboratory of Surgery, The General Hospital of Ningxia Medical University, Yinchuan, China.,Faculty of Health Science, University of Macau, Macau, China
| | - Keqiang Zhang
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, CA, USA.
| | - Wendong Li
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, CA, USA
| | - Yunze Liu
- Faculty of Health Science, University of Macau, Macau, China
| | - Rajendra P Pangeni
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, CA, USA
| | - Aimin Li
- Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA
| | - Leonidas Arvanitis
- Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, CA, USA.
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Sun T, Zhang K, Pangeni RP, Wu J, Li W, Du Y, Guo Y, Chaurasiya S, Arvanitis L, Raz DJ. G9a Promotes Invasion and Metastasis of Non-Small Cell Lung Cancer through Enhancing Focal Adhesion Kinase Activation via NF-κB Signaling Pathway. Mol Cancer Res 2020; 19:429-440. [PMID: 33298547 DOI: 10.1158/1541-7786.mcr-20-0557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/15/2020] [Accepted: 12/02/2020] [Indexed: 11/16/2022] [Imported: 08/29/2023]
Abstract
Potential roles of euchromatic histone methyltransferase 2 (EHMT2 or G9a) in invasion and metastasis are not well understood in non-small cell lung cancer (NSCLC). Here, we investigated the effect and underlying mechanisms of G9a and therapeutic implications of targeting G9a in the invasion and metastasis of NSCLC. Overexpression of G9a significantly enhanced in vitro proliferation and invasion, while knockdown of G9a drastically suppressed in vivo growth and metastasis of A549 and H1299 NSCLC cells. Knockdown or inhibition of G9a significantly decreased the expression of focal adhesion kinase (FAK) protein and activation of FAK pathway. In addition, defactinib, a potent FAK inhibitor, partially abolished the G9a-enhanced invasion in these NSCLC cells. Furthermore, targeting G9a was found to suppress NF-κB transcriptional activity in NSCLC cells through stabilizing NF-κB inhibitor alpha (IκBα), while an NF-κB inhibitor Parthenilide partially abolished the G9a-enhanced FAK activation, which suggests that G9a-enhanced invasion and activation of FAK is mediated by elevated NF-κB activity. Notably, a strong positive correlation between the IHC staining of G9a and phosphorylated FAK proteins was identified in H1299 xenografts and 159 cases of NSCLC tissues (R = 0.408). IMPLICATIONS: The findings of this study strongly demonstrate that G9a may promote invasion and metastasis of NSCLC cells by enhancing FAK signaling pathway via elevating NF-κB transcriptional activity, indicating potential significance and therapeutic implications of these pathways in the invasion and metastasis of NSCLCs that overexpress G9a protein.
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Affiliation(s)
- Ting Sun
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.,Laboratory of Surgery, the General Hospital of Ningxia Medical University, Yinchuan, China
| | - Keqiang Zhang
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
| | - Rajendra P Pangeni
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Jun Wu
- Division of Comparative Medicine, City of Hope National Medical Center, Duarte, California
| | - Wendong Li
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Yong Du
- Laboratory of Surgery, the General Hospital of Ningxia Medical University, Yinchuan, China
| | - Yuming Guo
- Division of Comparative Medicine, City of Hope National Medical Center, Duarte, California
| | | | - Leonidas Arvanitis
- Department of Pathology, City of Hope National Medical Center, Duarte, California
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
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Zhang K, Yang L, Wang J, Sun T, Guo Y, Nelson R, Tong TR, Pangeni R, Salgia R, Raz DJ. Ubiquitin-specific protease 22 is critical to in vivo angiogenesis, growth and metastasis of non-small cell lung cancer. Cell Commun Signal 2019; 17:167. [PMID: 31842906 PMCID: PMC6916027 DOI: 10.1186/s12964-019-0480-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/11/2019] [Indexed: 12/11/2022] [Imported: 08/29/2023] Open
Abstract
BACKGROUND Loss of monoubiquitination of histone H2B (H2Bub1) was found to be associated with poor differentiation, cancer stemness, and enhanced malignancy of non-small cell lung cancer (NSCLC). Herein, we investigated the biological significance and therapeutic implications of ubiquitin-specific protease 22 (USP22), an H2Bub1 deubiquitinase, in non-small cell lung cancer (NSCLC). METHODS USP22 expression and its clinical relevance were assessed in NSCLC patients. The effects of USP22 knockout on sensitivity to cisplatin and irradiation, and growth, metastasis of NSCLC xenografts, and survival of cancer-bearing mice were investigated. The underlying mechanisms of targeting USP22 were explored. RESULTS Overexpression of USP22 was observed in 49.0% (99/202) of NSCLC tissues; higher USP22 immunostaining was found to be associated with enhanced angiogenesis and recurrence of NSCLC. Notably, USP22 knockout dramatically suppressed in vitro proliferation, colony formation; and angiogenesis, growth, metastasis of A549 and H1299 in mouse xenograft model, and significantly prolonged survival of metastatic cancer-bearing mice. Furthermore, USP22 knockout significantly impaired non-homologous DNA damage repair capacity, enhanced cisplatin and irradiation-induced apoptosis in these cells. In terms of underlying mechanisms, RNA sequencing and gene ontology enrichment analysis demonstrated that USP22 knockout significantly suppressed angiogenesis, proliferation, EMT, RAS, c-Myc pathways, concurrently enhanced oxidative phosphorylation and tight junction pathways in A549 and H1299 NSCLC cells. Immunoblot analysis confirmed that USP22 knockout upregulated E-cadherin, p16; reduced ALDH1A3, Cyclin E1, c-Myc, and attenuated activation of AKT and ERK pathways in these cells. CONCLUSIONS Our findings suggest USP22 plays critical roles in the malignancy and progression of NSCLC and provide rationales for targeting USP22, which induces broad anti-cancer activities, as a novel therapeutic strategy for NSCLC patient.
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Affiliation(s)
- Keqiang Zhang
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California, USA.
| | - Lu Yang
- Department of System Biology, City of Hope National Medical Center, Duarte, California, USA
| | - Jinhui Wang
- The Integrative Genomics Core Laboratory of Department of Molecular Medicine, City of Hope National Medical Center, Duarte, California, USA
| | - Ting Sun
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California, USA.,Department of Surgery, the General Hospital of Ningxia Medical University, Yinchuan, China
| | - Yuming Guo
- Division of Comparative Medicine, City of Hope National Medical Center, Duarte, CA, USA
| | - Rebecca Nelson
- Department of Pathology, City of Hope National Medical Center, Duarte, California, USA
| | - Tommy R Tong
- Division of Biostatistics, City of Hope National Medical Center, Duarte, California, USA
| | - Rajendra Pangeni
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California, USA
| | - Ravi Salgia
- Department of Medical Oncology & Therapeutics Research, City of Hope National Medical Center, Duarte, California, USA
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California, USA.
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Zhang K, Wang J, Wang J, Luh F, Liu X, Yang L, Liu YR, Su L, Yang YCSH, Chu P, Yen Y. LKB1 deficiency promotes proliferation and invasion of glioblastoma through activation of mTOR and focal adhesion kinase signaling pathways. Am J Cancer Res 2019; 9:1650-1663. [PMID: 31497348 PMCID: PMC6726989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/28/2019] [Indexed: 06/10/2023] [Imported: 08/29/2023] Open
Abstract
Liver kinase B1 (LKB1), a serine/threonine kinase, is frequently inactivated in several types of human cancers. To date, inactivation of LKB1 tumor suppressor has rarely been reported in glioblastoma. In this study, we investigated LKB1 status, biological significance, and therapeutic implications in glioblastoma. Loss of LKB1 immunostaining was identified in 8.6% (5/58), while decrease of LKB1 immunostaining was found in 29.3% (17/58) of glioblastoma tissues. Notably, mining TCGA database of LKB1 expression in glioblastoma revealed that lower mRNA level of LKB1 was associated with shorter survival in glioblastoma. We found that knockdown of LKB1 significantly promoted in vitro proliferation, adhesion, invasion, and metformin-induced apoptosis, and simultaneously enhanced activation of ERK and mammalian-target of rapamycin (mTOR) signaling pathways in LKB1-compenent U87 and T98 glioblastoma cells. Moreover, global transcriptional profiling revealed that adhesion and cytoskeletal proteins such as Vinculin, Talin and signaling pathways including focal adhesion kinase (FAK), extracellular martrix (ECM) receptor interaction, and cellular motility were significantly enriched in U87 and T98 glioblastoma cells upon LKB1 knockdown. Additionally, we demonstrated that the enhanced activation of FAK by LKB1 knockdown was dependent on differentially expressed cytoskeletal proteins in these glioblastoma cells. Importantly, we further found that mTOR1 inhibitor rapamycin dominantly inhibited in vitro cellular proliferation, while FAK inhibitor PF-573288 drastically decreased invasion of LKB1-attenuated glioblastoma cells. Therefore, downregulation of LKB1 may contribute to the pathogenesis and malignancy of glioblastoma and may have potential implications for stratification and treatment of glioblastoma patients.
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Affiliation(s)
- Keqiang Zhang
- Department of Surgery, City of Hope National Medical CenterDuarte, CA, USA
| | - Jinghan Wang
- The First Department of Biliary Surgery, Eastern Hepatobiliary Surgical HospitalShanghai, China
| | - Jinhui Wang
- The Integrative Genomics Core Lab, City of Hope National Medical CenterDuarte, CA, USA
| | - Frank Luh
- Sino-American Cancer FoundationTemple City, CA, USA
| | - Xiyong Liu
- Sino-American Cancer FoundationTemple City, CA, USA
| | - Lu Yang
- Department of System Biology, City of Hope National Medical CenterDuarte, CA, USA
| | - Yun-Ru Liu
- Comprehensive Cancer Center, Taipei Medical UniversityTaipei, Taiwan
| | - Leila Su
- Sino-American Cancer FoundationTemple City, CA, USA
| | - Yu-Chen SH Yang
- PhD Program of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical UniversityTaipei, Taiwan
| | - Peiguo Chu
- Department of Pathology, City of Hope National Medical CenterDuarte, CA, USA
| | - Yun Yen
- Comprehensive Cancer Center, Taipei Medical UniversityTaipei, Taiwan
- PhD Program of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical UniversityTaipei, Taiwan
- Research Center of Cancer Translational Medicine, Taipei Medical UniversityTaipei, Taiwan
- Graduate Institute of Cancer Biology and Drug Discovery, Taipei Medical UniversityTaipei, Taiwan
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Zhang K, Wang J, Yang L, Yuan YC, Tong TR, Wu J, Yun X, Bonner M, Pangeni R, Liu Z, Yuchi T, Kim JY, Raz DJ. Targeting histone methyltransferase G9a inhibits growth and Wnt signaling pathway by epigenetically regulating HP1α and APC2 gene expression in non-small cell lung cancer. Mol Cancer 2018; 17:153. [PMID: 30348169 PMCID: PMC6198520 DOI: 10.1186/s12943-018-0896-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/25/2018] [Indexed: 11/10/2022] [Imported: 08/29/2023] Open
Abstract
BACKGROUND Dysregulated histone methyltransferase G9a may represent a potential cancer therapeutic target. The roles of G9a in tumorigenesis and therapeutics are not well understood in non-small cell lung cancer (NSCLC). Here we investigated the impact of G9a on tumor growth and signaling pathways in NSCLC. METHODS Immunohistochemistry analyzed G9a expression in NSCLC tissues. Both siRNA and selective inhibitor were used to target G9a. The impact of targeting G9a on key genes, signaling pathways and growth were investigated in NSCLC cells by RNA sequencing analysis, rescue experiments, and xenograft models. RESULTS Overexpression of G9a (≥ 5% of cancer cells showing positive staining) was found in 43.2% of 213 NSCLC tissues. Multiple tumor-associated genes including HP1α, APC2 are differentially expressed; and signaling pathways involved in cellular growth, adhesion, angiogenesis, hypoxia, apoptosis, and canonical Wnt signaling pathways are significantly altered in A549, H1299, and H1975 cells upon G9a knockdown. Additionally, targeting G9a by siRNA-mediated knockdown or by a selective G9a inhibitor UNC0638 significantly inhibited tumor growth, and dramatically suppressed Wnt signaling pathway in vitro and in vivo. Furthermore, we showed that treatment with UNC0638 restores the expression of APC2 expression in these cells through promoter demethylation. Restoring HP1α and silencing APC2 respectively attenuated the inhibitory effects on cell proliferation and Wnt signaling pathway in cancer cells in which G9a was silenced or suppressed. CONCLUSIONS These findings demonstrate that overexpressed G9a represents a promising therapeutic target, and targeting G9a potentially suppresses growth and Wnt signaling pathway partially through down-regulating HP1α and epigenetically restoring these tumor suppressors such as APC2 that are silenced in NSCLC.
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Affiliation(s)
- Keqiang Zhang
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA.
| | - Jinhui Wang
- The Integrative Genomics Core lab of Department of Molecular Medicine, City of Hope National Medical Center, Duarte, CA, USA
| | - Lu Yang
- The Integrative Genomics Core lab of Department of Molecular Medicine, City of Hope National Medical Center, Duarte, CA, USA
| | - Yate-Ching Yuan
- The Bioinformatics Core lab of Department of Molecular Medicine, City of Hope Medical Center, Duarte, CA, USA
| | - Tommy R Tong
- Department of Pathology, City of Hope Medical Center, Duarte, CA, USA
| | - Jun Wu
- Division of Comparative Medicine, City of Hope National Medical Center, Duarte, CA, USA
| | - Xinwei Yun
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA
| | - Melissa Bonner
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA
| | - Rajendra Pangeni
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA
| | - Zheng Liu
- The Bioinformatics Core lab of Department of Molecular Medicine, City of Hope Medical Center, Duarte, CA, USA
| | - Tiger Yuchi
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA
| | - Jae Y Kim
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope Medical Center, Duarte, CA, USA.
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Zhang K, Keymeulen S, Nelson R, Tong TR, Yuan YC, Yun X, Liu Z, Lopez J, Raz DJ, Kim JY. Overexpression of Flap Endonuclease 1 Correlates with Enhanced Proliferation and Poor Prognosis of Non-Small-Cell Lung Cancer. Am J Pathol 2017; 188:242-251. [PMID: 29037854 DOI: 10.1016/j.ajpath.2017.09.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/14/2017] [Accepted: 09/21/2017] [Indexed: 01/31/2023] [Imported: 08/29/2023]
Abstract
Flap endonuclease 1 (FEN1) plays a crucial role in both DNA replication and damage repair. In this study, FEN1 expression and its clinical-pathologic significance in non-small-cell lung cancer (NSCLC) was investigated. Quantitative RT-PCR and immunohistochemistry analysis identified that both FEN1 mRNA and protein were highly overexpressed in about 36% of 136 cancer tissues compared to adjacent tissues, in which FEN1 was generally undetectable. Notably, patients with FEN1-overexpressed cancers were prone to have poor differentiation and poor prognosis. A strong positive correlation between the levels of FEN1 and Ki-67 staining was identified in these NSCLC tissues (r = 0.485), suggesting overexpressed FEN1 conferred a proliferative advantage to NSCLC. Furthermore, knockdown of FEN1 resulted in G1/S or G2/M phase cell cycle arrest and suppressed in vitro cellular proliferation in NSCLC cancer cells. Consistently, a selective FEN1 inhibitor was shown to effectively inhibit cellular proliferation of NSCLC cells in a dose-dependent manner. Additionally, knockdown of FEN1 significantly attenuated homologous DNA repair efficiency and enhanced cytotoxic effects of cisplatin in NSCLC cells. Taken together, these findings have indicated that overexpressed FEN1 represents a prognostic biomarker and potential therapeutic target for NSCLC treatment, which warrants further study.
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Affiliation(s)
- Keqiang Zhang
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
| | - Sawa Keymeulen
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Rebecca Nelson
- Division of Biostatistics, City of Hope National Medical Center, Duarte, California
| | - Tommy R Tong
- Department of Pathology, City of Hope National Medical Center, Duarte, California
| | - Yate-Ching Yuan
- Bioinformatics Core Facility, Department of Molecular Medicine, City of Hope National Medical Center, Duarte, California
| | - Xinwei Yun
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Zheng Liu
- Bioinformatics Core Facility, Department of Molecular Medicine, City of Hope National Medical Center, Duarte, California
| | - Joshua Lopez
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Jae Y Kim
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
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Zhang K, Hu S, Wu J, Chen L, Lu J, Wang X, Liu X, Zhou B, Yen Y. Overexpression of RRM2 decreases thrombspondin-1 and increases VEGF production in human cancer cells in vitro and in vivo: implication of RRM2 in angiogenesis. Mol Cancer 2009; 8:11. [PMID: 19250552 PMCID: PMC2662784 DOI: 10.1186/1476-4598-8-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 02/28/2009] [Indexed: 11/10/2022] [Imported: 08/29/2023] Open
Abstract
Background In addition to its essential role in ribonucleotide reduction, ribonucleotide reductase (RNR) small subunit, RRM2, has been known to play a critical role in determining tumor malignancy. Overexpression of RRM2 significantly enhances the invasive and metastatic potential of tumor. Angiogenesis is critical to tumor malignancy; it plays an essential role in tumor growth and metastasis. It is important to investigate whether the angiogenic potential of tumor is affected by RRM2. Results We examined the expression of antiangiogenic thrombospondin-1 (TSP-1) and proangiogenic vascular endothelial growth factor (VEGF) in two RRM2-overexpressing KB cells: KB-M2-D and KB-HURs. We found that TSP-1 was significantly decreased in both KB-M2-D and KB-HURs cells compared to the parental KB and mock transfected KB-V. Simultaneously, RRM2-overexpressing KB cells showed increased production of VEGF mRNA and protein. In contrast, attenuating RRM2 expression via siRNA resulted in a significant increased TSP-1 expression in both KB and LNCaP cells; while the expression of VEGF by the two cells was significantly decreased under both normoxia and hypoxia. In comparison with KB-V, overexpression of RRM2 had no significant effect on proliferation in vitro, but it dramatically accelerated in vivo subcutaneous growth of KB-M2-D. KB-M2-D possessed more angiogenic potential than KB-V, as shown in vitro by its increased chemotaxis for endothelial cells and in vivo by the generation of more vascularized tumor xenografts. Conclusion These findings suggest a positive role of RRM2 in tumor angiogenesis and growth through regulation of the expression of TSP-1 and VEGF.
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Affiliation(s)
- Keqiang Zhang
- Department of Clinical & Molecular Pharmacology, City of Hope National Medical Center, Duarte, CA 91010, USA.
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