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The Role and Regulation of Thromboxane A2 Signaling in Cancer-Trojan Horses and Misdirection. Molecules 2022; 27:molecules27196234. [PMID: 36234768 PMCID: PMC9573598 DOI: 10.3390/molecules27196234] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/24/2022] Open
Abstract
Over the last two decades, there has been an increasing awareness of the role of eicosanoids in the development and progression of several types of cancer, including breast, prostate, lung, and colorectal cancers. Several processes involved in cancer development, such as cell growth, migration, and angiogenesis, are regulated by the arachidonic acid derivative thromboxane A2 (TXA2). Higher levels of circulating TXA2 are observed in patients with multiple cancers, and this is accompanied by overexpression of TXA2 synthase (TBXAS1, TXA2S) and/or TXA2 receptors (TBXA2R, TP). Overexpression of TXA2S or TP in tumor cells is generally associated with poor prognosis, reduced survival, and metastatic disease. However, the role of TXA2 signaling in the stroma during oncogenesis has been underappreciated. TXA2 signaling regulates the tumor microenvironment by modulating angiogenic potential, tumor ECM stiffness, and host immune response. Moreover, the by-products of TXA2S are highly mutagenic and oncogenic, adding to the overall phenotype where TXA2 synthesis promotes tumor formation at various levels. The stability of synthetic enzymes and receptors in this pathway in most cancers (with few mutations reported) suggests that TXA2 signaling is a viable target for adjunct therapy in various tumors to reduce immune evasion, primary tumor growth, and metastasis.
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Wang Q, Morris RJ, Bode AM, Zhang T. Prostaglandin Pathways: Opportunities for Cancer Prevention and Therapy. Cancer Res 2021; 82:949-965. [PMID: 34949672 DOI: 10.1158/0008-5472.can-21-2297] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 10/27/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022]
Abstract
Because of profound effects observed in carcinogenesis, prostaglandins (PGs), prostaglandin-endoperoxide synthases, and PG receptors are implicated in cancer development and progression. Understanding the molecular mechanisms of PG actions has potential clinical relevance for cancer prevention and therapy. This review focuses on the current status of PG signaling pathways in modulating cancer progression and aims to provide insights into the mechanistic actions of PGs and their receptors in influencing tumor progression. We also examine several small molecules identified as having anticancer activity that target prostaglandin receptors. The literature suggests that targeting PG pathways could provide opportunities for cancer prevention and therapy.
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Affiliation(s)
- Qiushi Wang
- The Hormel Institute, University of Minnesota
| | | | - Ann M Bode
- The Hormel Institute, University of Minnesota
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Role of Nurr1 in Carcinogenesis and Tumor Immunology: A State of the Art Review. Cancers (Basel) 2020; 12:cancers12103044. [PMID: 33086676 PMCID: PMC7590204 DOI: 10.3390/cancers12103044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Nuclear receptor related-1 protein (Nurr1) emerges as a therapeutic target in multiple malignancies and immunotherapies. Previous studies have highlighted its association with clinicopathological parameters, tumorigenesis and therapeutic resistance in cancers. In addition, recent studies unraveled its contribution to the suppression of antitumor immunity, suggesting that inhibition of Nurr1 is a potential method to repress cancer aggressiveness and disrupt tumor immune tolerance. In line with this evidence, the present review provides the roles of Nurr1 in tumor progression and the associated underlying molecular mechanisms. Moreover, the significance of Nurr1 in promoting immune tolerance and potential strategies for Nurr1 inhibition are highlighted. Abstract Nuclear receptor related-1 protein (Nurr1), coded by an early response gene, is involved in multiple cellular and physiological functions, including proliferation, survival, and self-renewal. Dysregulation of Nurr1 has been frequently observed in many cancers and is attributed to multiple transcriptional and post-transcriptional mechanisms. Besides, Nurr1 exhibits extensive crosstalk with many oncogenic and tumor suppressor molecules, which contribute to its potential pro-malignant behaviors. Furthermore, Nurr1 is a key player in attenuating antitumor immune responses. It not only potentiates immunosuppressive functions of regulatory T cells but also dampens the activity of cytotoxic T cells. The selective accessibility of chromatin by Nurr1 in T cells is closely associated with cell exhaustion and poor efficacy of cancer immunotherapy. In this review, we summarize the reported findings of Nurr1 in different malignancies, the mechanisms that regulate Nurr1 expression, and the downstream signaling pathways that Nurr1 employs to promote a wide range of malignant phenotypes. We also give an overview of the association between Nurr1 and antitumor immunity and discuss the inhibition of Nurr1 as a potential immunotherapeutic strategy.
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Zhang Y, Yan WT, Yang ZY, Li YL, Tan XN, Jiang J, Zhang Y, Qi XW. The role of WT1 in breast cancer: clinical implications, biological effects and molecular mechanism. Int J Biol Sci 2020; 16:1474-1480. [PMID: 32210734 PMCID: PMC7085227 DOI: 10.7150/ijbs.39958] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 01/22/2020] [Indexed: 02/06/2023] Open
Abstract
Although Wilms' tumor gene 1 (WT1) was first cloned and identified as a tumor suppressor gene in nephroblastoma, subsequent studies have demonstrated that it can also play an oncogenic role in leukemia and various solid tumors. WT1 exerts biological functions with high tissue- and cell-specificity. This article reviews the relationship between WT1 and breast cancer from two aspects: (1) clinical application of WT1, including the relationship between expression of WT1 and prognosis of breast cancer patients, and its effectiveness as a target for comprehensive therapy of breast cancer; (2) the biological effects and molecular mechanisms of WT1 in the development and progression of breast cancer, including proliferation, apoptosis, invasion, and metastasis of breast cancer cells.
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Affiliation(s)
- Ye Zhang
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Wen-Ting Yan
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Ze-Yu Yang
- Breast and Thyroid Surgery, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing 400013, China
| | - Yan-Ling Li
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Xuan-Ni Tan
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Jun Jiang
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Yi Zhang
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
| | - Xiao-Wei Qi
- Breast and Thyroid Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
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Gutierrez-Pajares JL, Ben Hassen C, Oger C, Galano JM, Durand T, Frank PG. Oxidized Products of α-Linolenic Acid Negatively Regulate Cellular Survival and Motility of Breast Cancer Cells. Biomolecules 2019; 10:biom10010050. [PMID: 31905626 PMCID: PMC7023043 DOI: 10.3390/biom10010050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 12/09/2022] Open
Abstract
Despite recent advances in our understanding of the biological processes leading to the development and progression of cancer, there is still a need for new and effective agents to treat this disease. Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are non-enzymatically oxidized products of α-linolenic acid that are present in seeds and vegetable oils. They have been shown to possess anti-inflammatory and apoptosis-promoting activities in macrophages and leukemia cells, respectively. In this work, seven PhytoPs (PP1–PP7) and one PhytoFs (PF1) were evaluated for their cytotoxic, chemosensitization, and anti-migratory activities using the MCF-7 and MDA-MB-231 breast cancer cell lines. Among the tested compounds, only three PhytoPs had a significant effect on cell viability compared to the control group: Ent-9-L1-PhytoP (PP6) decreased cell viability in both cell lines, while 16-F1t-PhytoP (PP1) and 9-L1-PhytoP (PP5) decreased viability of MCF-7 and MDA-MB-231 cells, respectively. When combined with a sub-cytotoxic dose of doxorubicin, these three PhytoPs displayed significantly enhanced cytotoxic effects on MCF-7 cells while the chemotherapeutic drug alone had no effect. In cellular motility assays, Ent-9-(RS)-12-epi-ST-Δ10-13-PhytoF could significantly inhibit cellular migration of MDA-MB-231 cells. In addition, Ent-9-(RS)-12-epi-ST-Δ10-13-PhytoF also enhanced cellular adhesion of MDA-MB-231 cells.
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Affiliation(s)
| | - Celine Ben Hassen
- INSERM, Faculté de Médecine, Université de Tours, UMR1069 Tours, France
| | - Camille Oger
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM Faculté de Pharmacie, UMR5247 Montpellier, France
| | - Jean-Marie Galano
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM Faculté de Pharmacie, UMR5247 Montpellier, France
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM Faculté de Pharmacie, UMR5247 Montpellier, France
| | - Philippe G Frank
- INSERM, Faculté de Médecine, Université de Tours, UMR1069 Tours, France
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Mulvaney EP, O'Sullivan ÁG, Eivers SB, Reid HM, Kinsella BT. Differential expression of the TPα and TPβ isoforms of the human T Prostanoid receptor during chronic inflammation of the prostate: Role for FOXP1 in the transcriptional regulation of TPβ during monocyte-macrophage differentiation. Exp Mol Pathol 2019; 110:104277. [PMID: 31271729 DOI: 10.1016/j.yexmp.2019.104277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/21/2019] [Accepted: 06/22/2019] [Indexed: 11/16/2022]
Abstract
Inflammation is linked to prostate cancer (PCa) and to other diseases of the prostate. The prostanoid thromboxane (TX)A2 is a pro-inflammatory mediator implicated in several prostatic diseases, including PCa. TXA2 signals through the TPα and TPβ isoforms of the T Prostanoid receptor (TP) which exhibit several functional differences and transcriptionally regulated by distinct promoters Prm1 and Prm3, respectively, within the TBXA2R gene. This study examined the expression of TPα and TPβ in inflammatory infiltrates within human prostate tissue. Strikingly, TPβ expression was detected in 94% of infiltrates, including in B- and T-lymphocytes and macrophages. In contrast, TPα was more variably expressed and, where present, expression was mainly confined to macrophages. To gain molecular insight into these findings, expression of TPα and TPβ was evaluated as a function of monocyte-to-macrophage differentiation in THP-1 cells. Expression of both TPα and TPβ was upregulated following phorbol-12-myristate-13-acetate (PMA)-induced differentiation of monocytic THP-1 to their macrophage lineage. Furthermore, FOXP1, an essential transcriptional regulator down-regulated during monocyte-to-macrophage differentiation, was identified as a key trans-acting factor regulating TPβ expression through Prm3 in THP-1 cells. Knockdown of FOXP1 increased TPβ, but not TPα, expression in THP-1 cells, while genetic reporter and chromatin immunoprecipitation (ChIP) analyses established that FOXP1 exerts its repressive effect on TPβ through binding to four cis-elements within Prm3. Collectively, FOXP1 functions as a transcriptional repressor of TPβ in monocytes. This repression is lifted in differentiated macrophages, allowing for upregulation of TPβ expression and possibly accounting for the prominent expression of TPβ in prostate tissue-resident macrophages.
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Affiliation(s)
- Eamon P Mulvaney
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Áine G O'Sullivan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sarah B Eivers
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Helen M Reid
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - B Therese Kinsella
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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Mulvaney EP, Shilling C, Eivers SB, Perry AS, Bjartell A, Kay EW, Watson RW, Kinsella BT. Expression of the TPα and TPβ isoforms of the thromboxane prostanoid receptor (TP) in prostate cancer: clinical significance and diagnostic potential. Oncotarget 2018; 7:73171-73187. [PMID: 27689401 PMCID: PMC5341971 DOI: 10.18632/oncotarget.12256] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022] Open
Abstract
The prostanoid thromboxane (TX) A2 plays a central role in haemostasis and is increasingly implicated in cancer progression. TXA2 signals through two T Prostanoid receptor (TP) isoforms termed TPα and TPβ, with both encoded by the TBXA2R gene. Despite exhibiting several functional and regulatory differences, the role of the individual TP isoforms in neoplastic diseases is largely unknown. This study evaluated expression of the TPα and TPβ isoforms in tumour microarrays of the benign prostate and different pathological (Gleason) grades of prostate cancer (PCa). Expression of TPβ was significantly increased in PCa relative to benign tissue and strongly correlated with increasing Gleason grade. Furthermore, higher TPβ expression was associated with increased risk of biochemical recurrence (BCR) and significantly shorter disease-free survival time in patients post-surgery. While TPα was more variably expressed than TPβ in PCa, increased/high TPα expression within the tumour also trended toward increased BCR and shorter disease-free survival time. Comparative genomic CpG DNA methylation analysis revealed substantial differences in the extent of methylation of the promoter regions of the TBXA2R that specifically regulate expression of TPα and TPβ, respectively, both in benign prostate and in clinically-derived tissue representative of precursor lesions and progressive stages of PCa. Collectively, TPα and TPβ expression is differentially regulated both in the benign and tumourigenic prostate, and coincides with clinical pathology and altered CpG methylation of the TBXA2R gene. Analysis of TPβ, or a combination of TPα/TPβ, expression levels may have significant clinical potential as a diagnostic biomarker and predictor of PCa disease recurrence.
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Affiliation(s)
- Eamon P Mulvaney
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Christine Shilling
- Department of Pathology, Beaumont Hospital and Royal College of Surgeons, Dublin, Ireland
| | - Sarah B Eivers
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Antoinette S Perry
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Anders Bjartell
- Department of Translational Medicine, Division of Urological Cancers, Skåne University Hospital Malmö, Lund University, Lund, Sweden
| | - Elaine W Kay
- Department of Pathology, Beaumont Hospital and Royal College of Surgeons, Dublin, Ireland
| | - R William Watson
- UCD School of Medicine, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - B Therese Kinsella
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
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O'Sullivan AG, Eivers SB, Mulvaney EP, Kinsella BT. Regulated expression of the TPβ isoform of the human T prostanoid receptor by the tumour suppressors FOXP1 and NKX3.1: Implications for the role of thromboxane in prostate cancer. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3153-3169. [PMID: 28890397 DOI: 10.1016/j.bbadis.2017.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/16/2017] [Accepted: 09/07/2017] [Indexed: 12/13/2022]
Abstract
The prostanoid thromboxane (TX)A2 signals through the TPα and TPβ isoforms of T Prostanoid receptor (TP) that are transcriptionally regulated by distinct promoters termed Prm1 and Prm3, respectively, within the TBXA2R gene. We recently demonstrated that expression of TPα and TPβ is increased in PCa, differentially correlating with Gleason grade and with altered CpG methylation of the individual Prm1/Prm3 regions within the TBXA2R. The current study sought to localise the sites of CpG methylation within Prm1 and Prm3, and to identify the main transcription factors regulating TPβ expression through Prm3 in the prostate adenocarcinoma PC-3 and LNCaP cell lines. Bisulfite sequencing revealed extensive differences in the pattern and status of CpG methylation of the individual Prm1 and Prm3 regions that regulate TPα and TPβ expression, respectively, within the TBXA2R. More specifically, Prm1 is predominantly hypomethylated while Prm3 is hypermethylated across its entire sequence in PC-3 and LNCaP cells. Furthermore, the tumour suppressors FOXP1 and NKX3.1, strongly implicated in PCa development, were identified as key transcription factors regulating TPβ expression through Prm3 in both PCa cell lines. Specific siRNA-disruption of FOXP1 and NKX3.1 each coincided with up-regulated TPβ protein and mRNA expression, while genetic-reporter and chromatin immunoprecipitation (ChIP) analyses confirmed that both FOXP1 and NKX3.1 bind to cis‑elements within Prm3 to transcriptionally repress TPβ in the PCa lines. Collectively these data identify Prm3/TPβ as a bona fide target of FOXP1 and NKX3.1 regulation, providing a mechanistic basis, at least in part, for the highly significant upregulation of TPβ expression in PCa.
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Affiliation(s)
- Aine G O'Sullivan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sarah B Eivers
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Eamon P Mulvaney
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - B Therese Kinsella
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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Mishra S, Kaddi CD, Wang MD. Pan-cancer analysis for studying cancer stage using protein and gene expression data. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:2440-2443. [PMID: 28268818 DOI: 10.1109/embc.2016.7591223] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Pan-cancer analyses attempt to discover similar features among multiple cancers to identify fundamental patterns common to cancer development and progression. A pan-cancer analysis integrating both protein expression and transcriptomic data is important because it can identify genes that are linked to proteins potentially responsible for a patient's status. This study aims to identify differentially expressed (DE) genes between early and advanced cases of multiple cancer types through the usage of RNA sequencing data. The relevance of these genes is further investigated by developing predictive models using K-nearest neighbor and linear discriminant analysis classifiers. The use of cancer-specific and non-cancer specific features resulted in several moderately performing models. Highlighted genes were further investigated to determine if they encoded for proteins identified in a previously conducted pan-cancer analysis. The results of this study suggest that a pan-cancer analysis may be highly complementary to standard analyses of individual cancers for identifying biologically relevant DE genes and can assist in developing effective predictive models for cancer progression.
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Protein kinase C-related kinase 1 and 2 play an essential role in thromboxane-mediated neoplastic responses in prostate cancer. Oncotarget 2016; 6:26437-56. [PMID: 26296974 PMCID: PMC4694913 DOI: 10.18632/oncotarget.4664] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 07/06/2015] [Indexed: 01/03/2023] Open
Abstract
The prostanoid thromboxane (TX) A2 is increasingly implicated in neoplastic progression, including prostate cancer (PCa). Mechanistically, we recently identified protein kinase C-related kinase (PRK) 1 as a functional interactant of both the TPα and TPβ isoforms of the human T prostanoid receptor (TP). The interaction with PRK1 was not only essential for TPα/TPβ-induced PCa cell migration but also enabled the TXA2-TP axis to induce phosphorylation of histone H3 at Thr11 (H3Thr11), an epigenetic marker both essential for and previously exclusively associated with androgen-induced chromatin remodelling and transcriptional activation. PRK1 is a member of a subfamily of three structurally related kinases comprising PRK1/PKNα, PRK2/PKNγ and PRK3/PKNβ that are widely yet differentially implicated in various cancers. Hence, focusing on the setting of prostate cancer, this study investigated whether TPα and/or TPβ might also complex with PRK2 and PRK3 to regulate their activity and neoplastic responses. While TPα and TPβ were found in immune complexes with PRK1, PRK2 and PRK3 to regulate their activation and signalling, they do so differentially and in a TP agonist-regulated manner dependent on the T-loop activation status of the PRKs but independent of their kinase activity. Furthermore, TXA2-mediated neoplastic responses in prostate adenocarcinoma PC-3 cells, including histone H3Thr11 phosphorylation, was found to occur through a PRK1- and PRK2-, but not PRK3-, dependent mechanism. Collectively, these data suggest that TXA2 acts as both a neoplastic and epigenetic regulator and provides a mechanistic explanation, at least in part, for the prophylactic benefits of Aspirin in reducing the risk of certain cancers.
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