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The Klebsiella mannose phosphotransferase system promotes proliferation and the production of extracellular polymeric substances from mannose, facilitating adaptation to the host environment. J Oral Biosci 2024; 66:119-125. [PMID: 38246421 DOI: 10.1016/j.job.2024.01.003] [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: 12/01/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/23/2024]
Abstract
OBJECTIVES Klebsiella spp., an opportunistic infectious organism, is commensal in the nasal and oral cavities of humans. Recently, it has been reported that oral Klebsiella spp. ectopically colonize the intestinal tract and induce the accumulation of intestinal Th1 cells. For oral bacteria to colonize the intestinal tract, they need to compete for nutrients with indigenous intestinal bacteria. Therefore, we focused on mannose, a mucus-derived sugar, and the mannose phosphotransferase system (PTS) (ManXYZ), a mechanism for mannose uptake, in terms of their effects on intestinal colonization and immune responses to Klebsiella spp. METHODS We generated a Klebsiella manXYZ-deficient strain and investigated whether the utilization of intestinal mucus-derived sugars is associated with the growth. Furthermore, we examine the virulence of this organism in the mouse intestinal tract, especially the ability to colonize the host using competition assay. RESULTS We found that Klebsiella ManXYZ is a PTS that specifically takes up mannose and glucosamine. Through ManXYZ, mannose was used for bacterial growth and the upregulated production of extracellular polymeric substances. In vivo competition assays showed that mannose metabolism promoted intestinal colonization. However, ManXYZ was not involved in Th1 and Th17 induction in the intestinal tract. CONCLUSION The fundamental roles of ManXYZ were to ensure that mannose, which is present in the host, is made available for bacterial growth, to promote the production of extracellular polymeric substances, thus facilitating bacterial adaptation to the host environment.
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Oral commensal bacterial flora is responsible for peripheral differentiation of neutrophils in the oral mucosa in the steady state. J Oral Biosci 2023; 65:119-125. [PMID: 36464149 DOI: 10.1016/j.job.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022]
Abstract
OBJECTIVES Commensal bacteria in the host body play a fundamental role in the differentiation and maintenance of the immune system. Studies on intestinal immunity have revealed that, under steady-state conditions, microflora have an important role in the maintenance of health. However, the role of oral commensal bacteria on the oral immune system is still unclear. Here, we clarify the interactions between commensal bacteria and the oral mucosal immune system under steady-state conditions. METHODS We used germ-free mice that had never been exposed to bacteria and conventional mice grown with normal bacterial flora. Oral cells were isolated from the oral mucosa, stained with specific antibodies, and analyzed by flow cytometry. For the detection of myeloperoxidase and intracellular cytokines, oral cells were stimulated with N-formyl-methionine-leucyl-phenylalanine and phorbol 12-myristate 13-acetate/ionomycin, respectively. RESULTS We found that the oral mucosa harbored more neutrophils in germ-free mice than in conventional mice. However, the majority of neutrophils in the germ-free oral mucosa exhibited an immature phenotype. Other immune cells, including macrophages, T cells, and B cells, in the oral mucosa of germ-free mice showed similar differentiation to those in conventional mice. These results indicate that in the steady-state oral mucosa, the normal commensal flora promote the peripheral differentiation of neutrophils. CONCLUSIONS The presence of commensal flora is critical for the development of adequate immune system in the oral mucosa.
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The downregulation of NADPH oxidase Nox4 during hypoxia in hemangioendothelioma cells: a possible role of p22 phox on Nox4 protein stability. Free Radic Res 2022; 55:996-1004. [PMID: 35012414 DOI: 10.1080/10715762.2021.2009116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
NADPH oxidase (Nox) 4 produces H2O2 by forming a heterodimer with p22phox and is involved in hemangioendothelioma development through monocyte chemoattractant protein-1 (MCP-1) upregulation. Here, we show that Nox4 protein levels were maintained by p22phox in hemangioendothelioma cells and Nox4 protein stability was dependent on p22phox coexpression. Conversely, the degradation of Nox4 monomer was enhanced by p22phox knockdown. Under hypoxic conditions in hemangioendothelioma cells, p22phox was downregulated at the mRNA and protein levels. Downregulation of p22phox protein resulted in the enhanced degradation of Nox4 protein in hypoxia-treated hemangioendothelioma cells. In contrast, Nox2, a Nox isoform, was not altered at the protein level under hypoxic conditions. Nox2 exhibited a higher affinity for p22phox compared with Nox4, suggesting that when coexpressed with Nox4 in the same cells, Nox2 acts as a competitor. Nox2 knockdown restored Nox4 protein levels partially reduced by hypoxic treatment. Thus, Nox4 protein levels were attenuated in hypoxia-treated cells resulting from p22phox depletion. MCP-1 secretion was decreased concurrently with hypoxia-induced Nox4 downregulation compared with that under normoxia.
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Coculture in vitro with endothelial cells induces cytarabine resistance of acute myeloid leukemia cells in a VEGF-A/VEGFR-2 signaling-independent manner. Biochem Biophys Res Commun 2022; 587:78-84. [PMID: 34872003 DOI: 10.1016/j.bbrc.2021.11.090] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/16/2021] [Accepted: 11/25/2021] [Indexed: 12/28/2022]
Abstract
An interaction between acute myeloid leukemia (AML) cells and endothelial cells in the bone marrow seems to play a critical role in chemosensitivity on leukemia treatment. The endothelial niche reportedly enhances the paracrine action of the soluble secretory proteins responsible for chemoresistance in a vascular endothelial growth factor A (VEGF-A)/VEGF receptor 2 (VEGFR-2) signaling pathway-dependent manner. To further investigate the contribution of VEGF-A/VEGFR-2 signaling to the chemoresistance of AML cells, a biochemical assay system in which the AML cells were cocultured with human endothelial EA.hy926 cells in a monolayer was developed. By coculture with EA.hy926 cells, this study revealed that the AML cells resisted apoptosis induced by the anticancer drug cytarabine. SU4312, a VEGFR-2 inhibitor, attenuated VEGFR-2 phosphorylation and VEGF-A/VEGFR-2 signaling-dependent endothelial cell migration; thus, this inhibitor was observed to block VEGF-A/VEGFR-2 signaling. Interestingly, this inhibitor did not reverse the chemoresistance. When VEGFR-2 was knocked out in EA.hy926 cells using the CRISPR-Cas9 system, the cytarabine-induced apoptosis of AML cells did not significantly change compared with that of wild-type cells. Thus, coculture-induced chemoresistance appears to be independent of VEGF-A/VEGFR-2 signaling. When the transwell, a coculturing device, separated the AML cells from the EA.hy926 cells in a monolayer, the coculture-induced chemoresistance was inhibited. Given that the migration of VEGF-A/VEGFR-2 signaling-dependent endothelial cells is necessary for the endothelial niche formation in the bone marrow, VEGF-A/VEGFR-2 signaling contributes to chemoresistance by mediating the niche formation process, but not to the chemoresistance of AML cells in the niche.
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Profile of androgen receptor activators identified using high-throughput screen. Andrologia 2020; 53:e13856. [PMID: 33079406 DOI: 10.1111/and.13856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 11/30/2022] Open
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High-throughput screen identifies 5-HT receptor as a modulator of AR and a therapeutic target for prostate cancer. Prostate 2020; 80:885-894. [PMID: 32483877 DOI: 10.1002/pros.24022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/18/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND Eradication of persistent androgen receptor (AR) activity in castration-resistant prostate cancer may be a promising strategy to overcome castration resistance. We aimed to identify novel compounds that inhibit AR activity and could be potential therapeutic agents for prostate cancer. METHODS A high-throughput screening system involving cell lines stably expressing AR protein and AR-responsive luciferase was employed for the 1260 compound library. Molecular and antitumor effects on candidate pathways that interacted with AR signaling were examined in prostate cancer cells expressing AR. RESULTS The high-throughput screening identified various potential compounds that interfered with AR signaling through known and novel pathways. Among them, a 5-hydroxytryptamine 5A (5-HT5A) receptor antagonist suppressed AR activity through protein kinase A signaling, which was confirmed by 5-HT5A receptor knockdown. Consistently, 5-HT5A receptor inhibitors showed cytotoxic effects toward prostate cancer cells. CONCLUSIONS Taken together, this study identifies 5-HT5A receptor as a promising therapeutic target for prostate cancer via its interaction with AR signaling.
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Extracellular calcium stimulates osteogenic differentiation of human adipose-derived stem cells by enhancing bone morphogenetic protein-2 expression. Cell Calcium 2019; 83:102058. [DOI: 10.1016/j.ceca.2019.102058] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 06/19/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022]
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Mirabegron induces relaxant effects via cAMP signaling-dependent and -independent pathways in detrusor smooth muscle. Low Urin Tract Symptoms 2019; 11:O209-O217. [PMID: 30632283 DOI: 10.1111/luts.12247] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/31/2018] [Accepted: 11/05/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVE We previously found that mirabegron exerts a relaxant effect in the presence of the β3 -adrenoceptor antagonist SR58894A during carbachol-induced contraction in human and pig detrusor. The aim of this study was to explore the possible mechanism underlying the relaxant effects of mirabegron using detrusor smooth muscle. METHODS Human tissue was obtained from urinary bladders of patients undergoing radical cystectomy at Kyushu University and Harasanshin Hospital. Pig tissue was obtained from an abattoir. Tension force (organ bath experiments) was measured in intact or permeabilised (α-toxin or β-escin) detrusor smooth muscle strips. The contribution of cAMP-dependent signaling and the inhibition of Ca2+ sensitization to the relaxant effects of mirabegron were characterized using 1 μM SR58894A, 100 μM SQ22536 (an adenylyl cyclase inhibitor), 10 μM H-89 (a protein kinase [PK] A inhibitor), 10 μM Y-27632 (a selective Rho kinase inhibitor), and 10 μM GF-109203X (a selective PKC inhibitor). RESULTS 30 μM Mirabegron impaired carbachol (0.03-1 μM)-induced contraction in human detrusor smooth muscle. SR58894A only partially attenuated the relaxant effects of mirabegron in human and pig detrusor strips precontracted with 1 μM carbachol. In α-toxin-permeabilized detrusor strips, tension force at 1 μM [Ca2+ ]i was decreased by mirabegron in a concentration-dependent manner. The relaxant effect of mirabegron was only slightly attenuated by H-89 and not significantly affected by SQ22536. Y-27632 potentiated the relaxation response to mirabegron, but attenuated responses to cAMP; GF-109203X had little effect. Mirabegron but not cAMP had a notable relaxant effect in the pig detrusor smooth muscle permeabilized with β-escin. CONCLUSIONS Mirabegron-induced relaxation of pig and human detrusor smooth muscle occurs via both a β3 -adrenoceptor/cAMP-dependent and -independent pathway.
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Gene polymorphisms in antioxidant enzymes correlate with the efficacy of androgen-deprivation therapy for prostate cancer with implications of oxidative stress. Ann Oncol 2017; 28:569-575. [PMID: 27993795 DOI: 10.1093/annonc/mdw646] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Background Oxidative stress mitigated by antioxidant enzymes is thought to be involved in the progression to castration-resistant prostate cancer (CRPC) during androgen-deprivation therapy (ADT). This study investigated the association between genetic variations in antioxidant enzymes and the efficacy of ADT as well as its biological background. Patients and methods The non-synonymous or promoter-locating polymorphisms of antioxidant enzymes were examined as well as the time to CRPC progression and overall survival in 104 and 92 patients treated with ADT for metastatic and non-metastatic prostate cancer, respectively. In addition, intracellular reactive oxygen species and expression levels of antioxidant enzymes were examined in castration-resistant and enzalutamide-resistant cells. Results In metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 and CT/TT allele in CAT rs564250 were associated with a significantly lower risk of progression to CRPC and all-cause death compared with homozygotes of the major AA allele (hazard ratio [HR]; [95% confidence interval (CI)], 0.55 [0.34-0.86], P = 0.0086) and CC allele (HR; [95% CI], 0.48 [0.24-0.88], P = 0.016), respectively. On multivariate analyses, only GSTM3 rs7483 was associated with significant progression risk (AG/GG versus AA; HR; [95% CI], 0.45 [0.25-0.79], P = 0.0047) even after Bonferroni adjustment. In non-metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 was associated with a significantly lower risk of progression to CRPC (HR; [95% CI], 0.35 [0.10-0.93], P = 0.034) and all-cause death (HR; [95% CI], 0.26 [0.041-0.96], P = 0.043) compared with the AA allele. Intracellular reactive oxygen species levels were increased, accompanied with augmented GSTM3 expression in both castration-resistant and enzalutamide-resistant cells. Conclusions Differential activity of antioxidant enzymes caused by the polymorphism in GSTM3 may contribute to resistance to hormonal therapy through oxidative stress. The GSTM3 rs7483 polymorphism may be a promising biomarker for prostate cancer patients treated with ADT.
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A20 restores phorbol ester-induced differentiation of THP-1 cells in the absence of nuclear factor-κB activation. J Cell Biochem 2017; 119:1475-1487. [PMID: 28771803 DOI: 10.1002/jcb.26308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 08/02/2017] [Indexed: 11/06/2022]
Abstract
A20, also referred to as tumor necrosis factor alpha (TNFα)-induced protein 3 (TNFAIP3), is an ubiquitin-editing enzyme whose expression is enhanced by NF-κB activation, and plays an important role in silencing NF-κB activity. Another well-known role for A20 is to protect cells from TNFα-induced apoptosis. Depletion of NF-κB in differentiating U937 monocytic leukemia cells is known to cause apoptotic cell death; however, much remains to be explored about the molecules that are expressed in an NF-κB-dependent manner and which support monocyte-macrophage differentiation. Using the monocytic cell line THP-1, and peripheral blood monocytes, we show here a sustained increase in A20 expression during monocyte-macrophage differentiation, which coincided with high NF-κB-dependent transcriptional activity. Depletion of NF-κB by stable expression of a super-repressor form of IκBα in THP-1 cells caused remarkable cell death during phorbol 12-myristate 13-acetate (PMA)-induced differentiation. A20 expression in these cells did not alter this NF-κB suppression, but was sufficient to protect the cells and restore the cell surface expression of a differentiation marker (CD11b) and phagocytic activity. Mutational analyses revealed that this A20 activity requires the carboxy-terminal zinc-finger domain, but not its deubiquitinase activity. Based on these findings, we conclude that A20, when ectopically expressed, can support both survival and differentiation of THP-1 cells in the absence of sustained NF-κB activity.
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Glutathione Primes T Cell Metabolism for Inflammation. Immunity 2017; 46:675-689. [PMID: 28423341 DOI: 10.1016/j.immuni.2017.03.019] [Citation(s) in RCA: 266] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/31/2017] [Accepted: 03/29/2017] [Indexed: 01/19/2023]
Abstract
Activated T cells produce reactive oxygen species (ROS), which trigger the antioxidative glutathione (GSH) response necessary to buffer rising ROS and prevent cellular damage. We report that GSH is essential for T cell effector functions through its regulation of metabolic activity. Conditional gene targeting of the catalytic subunit of glutamate cysteine ligase (Gclc) blocked GSH production specifically in murine T cells. Gclc-deficient T cells initially underwent normal activation but could not meet their increased energy and biosynthetic requirements. GSH deficiency compromised the activation of mammalian target of rapamycin-1 (mTOR) and expression of NFAT and Myc transcription factors, abrogating the energy utilization and Myc-dependent metabolic reprogramming that allows activated T cells to switch to glycolysis and glutaminolysis. In vivo, T-cell-specific ablation of murine Gclc prevented autoimmune disease but blocked antiviral defense. The antioxidative GSH pathway thus plays an unexpected role in metabolic integration and reprogramming during inflammatory T cell responses.
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Equol inhibits prostate cancer growth through degradation of androgen receptor by S-phase kinase-associated protein 2. Cancer Sci 2016; 107:1022-8. [PMID: 27088761 PMCID: PMC4946716 DOI: 10.1111/cas.12948] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/08/2016] [Accepted: 04/12/2016] [Indexed: 12/19/2022] Open
Abstract
Chemopreventive and potential therapeutic effects of soy isoflavones have been shown to be effective in numerous preclinical studies as well as clinical studies in prostate cancer. Although the inhibition of androgen receptor signaling has been supposed as one mechanism underlying their effects, the precise mechanism of androgen receptor inhibition remains unclear. Thus, this study aimed to clarify their mechanism. Among soy isoflavones, equol suppressed androgen receptor as well as prostate-specific antigen expression most potently in androgen-dependent LNCaP cells. However, the inhibitory effect on androgen receptor expression and activity was less prominent in castration-resistant CxR and 22Rv1 cells. Consistently, cell proliferation was suppressed and cellular apoptosis was induced by equol in LNCaP cells, but less so in CxR and 22Rv1 cells. We revealed that the proteasome pathway through S-phase kinase-associated protein 2 (Skp2) was responsible for androgen receptor suppression. Taken together, soy isoflavones, especially equol, appear to be promising as chemopreventive and therapeutic agents for prostate cancer based on the fact that equol augments Skp2-mediated androgen receptor degradation. Moreover, because Skp2 expression was indicated to be crucial for the effect of soy isoflavones, soy isoflavones may be applicable for precancerous and cancerous prostates.
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Epithelial to Mesenchymal Transition in Clear Cell Renal Cell Carcinoma with Rhabdoid Features. Pathobiology 2016; 83:277-86. [DOI: 10.1159/000445752] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/23/2016] [Indexed: 11/19/2022] Open
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Potential Role for YB-1 in Castration-Resistant Prostate Cancer and Resistance to Enzalutamide Through the Androgen Receptor V7. J Natl Cancer Inst 2016; 108:djw005. [DOI: 10.1093/jnci/djw005] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 01/06/2016] [Indexed: 12/17/2022] Open
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Crosstalk between epithelial-mesenchymal transition and castration resistance mediated by Twist1/AR signaling in prostate cancer. Endocr Relat Cancer 2015; 22:889-900. [PMID: 26311513 DOI: 10.1530/erc-15-0225] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 08/26/2015] [Indexed: 02/04/2023]
Abstract
Although invasive and metastatic progression via the epithelial-mesenchymal transition (EMT) and acquisition of resistance to castration are both critical steps in prostate cancer, the molecular mechanism of this interaction remains unclear. In this study, we aimed to elucidate the interaction of signaling between castration resistance and EMT, and to apply this information to the development of a novel therapeutic concept using transforming growth factor-β (TGF-β) inhibitor SB525334 combined with androgen-deprivation therapy against prostate cancer using an in vivo model. This study revealed that an EMT inducer (TGF-β) induced full-length androgen receptor (AR) and AR variant expression. In addition, a highly invasive clone showed augmented full-length AR and AR variant expression as well as acquisition of castration resistance. Conversely, full-length AR and AR as well as Twist1 and mesenchymal molecules variant expression were up-regulated in castration-resistant LNCaP xenograft. Finally, TGF-β inhibitor suppressed Twist1 and AR expression as well as prostate cancer growth combined with castration. Taken together, these results demonstrate that Twist1/AR signaling was augmented in castration resistant as well as mesenchymal-phenotype prostate cancer, indicating the molecular mechanism of mutual and functional crosstalk between EMT and castration resistance, which may play a crucial role in prostate carcinogenesis and progression.
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MESH Headings
- Adenocarcinoma/drug therapy
- Adenocarcinoma/genetics
- Adenocarcinoma/pathology
- Adenocarcinoma/physiopathology
- Adenocarcinoma/surgery
- Androgens
- Animals
- Cell Line, Tumor
- Cell Transformation, Neoplastic
- Combined Modality Therapy
- Epithelial-Mesenchymal Transition/physiology
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- Imidazoles/pharmacology
- Imidazoles/therapeutic use
- Male
- Mice
- Mice, Nude
- Neoplasm Invasiveness
- Neoplasm Proteins/physiology
- Neoplasms, Hormone-Dependent/drug therapy
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/pathology
- Neoplasms, Hormone-Dependent/physiopathology
- Neoplasms, Hormone-Dependent/surgery
- Nuclear Proteins/physiology
- Orchiectomy
- Prostatic Neoplasms/drug therapy
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/pathology
- Prostatic Neoplasms/physiopathology
- Prostatic Neoplasms/surgery
- Quinoxalines/pharmacology
- Quinoxalines/therapeutic use
- RNA Interference
- RNA, Small Interfering/genetics
- Random Allocation
- Receptors, Androgen/biosynthesis
- Receptors, Androgen/chemistry
- Receptors, Androgen/genetics
- Receptors, Androgen/physiology
- Signal Transduction
- Transforming Growth Factor beta/antagonists & inhibitors
- Twist-Related Protein 1/physiology
- Xenograft Model Antitumor Assays
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SRD5A gene polymorphism in Japanese men predicts prognosis of metastatic prostate cancer with androgen-deprivation therapy. Eur J Cancer 2015; 51:1962-9. [DOI: 10.1016/j.ejca.2015.06.122] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/24/2015] [Accepted: 06/17/2015] [Indexed: 11/26/2022]
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Actions of cAMP on calcium sensitization in human detrusor smooth muscle contraction. BJU Int 2015; 117:179-91. [PMID: 25981809 DOI: 10.1111/bju.13180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To clarify the effect of cAMP on the Ca(2+) -sensitized smooth muscle contraction in human detrusor, as well as the role of novel exchange protein directly activated by cAMP (Epac) in cAMP-mediated relaxation. MATERIALS AND METHODS All experimental protocols to record isometric tension force were performed using α-toxin-permeabilized human detrusor smooth muscle strips. The mechanisms of cAMP-mediated suppression of Ca(2+) sensitization activated by 10 μm carbachol (CCh) and 100 μm GTP were studied using a selective rho kinase (ROK) inhibitor, Y-27632, and a selective protein kinase C (PKC) inhibitor, GF-109203X. The relaxation mechanisms were further probed using a selective protein kinase A (PKA) activator, 6-Bnz-cAMP and a selective Epac activator, 8-pCPT-2'-O-Me-cAMP. RESULTS We observed that CCh-induced Ca(2+) sensitization was inhibited by cAMP in a concentration-dependent manner. GF-109203X (10 μm) but not Y-27632 (10 μm) significantly enhanced the relaxation effect induced by cAMP (100 μm). 6-Bnz-cAMP (100 μm) predominantly decreased the tension force in comparison with 8-pCPT-2'-O-Me-cAMP (100 μm). CONCLUSIONS We showed that cAMP predominantly inhibited the ROK pathway but not the PKC pathway. The PKA-dependent pathway is dominant, while Epac plays a minor role in human detrusor smooth muscle Ca(2+) sensitization.
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Renal cancer treatment with recipient lymphocyte infusion enhanced the antitumor effect of nonmyeloablative allogeneic stem cell transplantation. Transpl Immunol 2015; 32:131-9. [DOI: 10.1016/j.trim.2014.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/07/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
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Abstract
Phorbol 12-myristate 13-acetate (PMA) induces cellular apoptosis in prostate cancer cells, the growth of which is governed by androgen/androgen receptor (AR) signaling, but the mechanism by which PMA exerts this effect remains unknown. Therefore, in this study, we investigated the mechanistic action of PMA in prostate cancer cells with regard to AR. We showed that PMA decreased E2F1 as well as AR expression in androgen-dependent prostate cancer LNCaP cells. Furthermore, PMA activated JNK and p53 signaling, resulting in the induction of cellular apoptosis. In LNCaP cells, androgen deprivation and a novel anti-androgen enzalutamide (MDV3100) augmented cellular apoptosis induced by PMA. Moreover, castration-resistant prostate cancer (CRPC) C4-2 cells were more sensitive to PMA compared with LNCaP cells and were sensitized to PMA by enzalutamide. Finally, the expression of PKC, E2F1, and AR was diminished in PMA-resistant cells, indicating that the gain of independence from PKC, E2F1, and AR functions leads to PMA resistance. In conclusion, PMA exerted its anti-cancer effects via the activation of pro-apoptotic JNK/p53 and inhibition of pro-proliferative E2F1/AR in prostate cancer cells including CRPC cells. The therapeutic effects of PMA were augmented by androgen deletion and enzalutamide in androgen-dependent prostate cancer cells, as well as by enzalutamide in castration-resistant cells. Taken together, PMA derivatives may be promising therapeutic agents for treating prostate cancer patients including CRPC patients.
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Inhibition of RSK/YB-1 signaling enhances the anti-cancer effect of enzalutamide in prostate cancer. Prostate 2014; 74:959-69. [PMID: 24740858 DOI: 10.1002/pros.22813] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/26/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Previously, we have shown that Y-box binding protein-1 (YB-1) regulates androgen receptor (AR) expression and contributes to castration resistance. However, the mechanism of YB-1 activation remains unknown. In this study, we aimed to elucidate the mechanism and role of YB-1 activation in relation to castration resistance as well as enzalutamide resistance, with a view to developing a novel therapeutic concept for castration-resistant prostate cancer (CRPC) treatment. METHODS The expression and phosphorylation levels of ribosomal S6 kinase 1 (RSK1), YB-1 and AR were examined by quantitative PCR and Western blotting using prostate cancer cells. In addition, the effects of YB-1 inhibition using specific siRNA and small molecule inhibitor SL0101 on AR expression as well as combination treatment with enzalutamide and SL0101 were examined. RESULTS We found that androgen deprivation, as well as treatment with the next-generation anti-androgen enzalutamide, induced RSK1 and YB-1 activation followed by AR induction, which could be reversed by YB-1 shutdown and RSK inhibitor SL0101. SL0101 and enzalutamide exerted a synergistic tumor-suppressive effect on cell proliferation in androgen-dependent prostate cancer LNCaP cells, as well as castration-resistant C4-2 cells. Furthermore, the phosphorylation levels of RSK1 and YB-1 were elevated in castration- and enzalutamide-resistant cells, compared with their parental cells. CONCLUSIONS Taken together, these findings indicate that RSK1/YB-1 signaling contributes to castration as well as enzalutamide resistance, and that the therapeutic targeting of RSK1/YB-1 signaling would be a promising novel therapy against prostate cancer, especially CRPC when combined with enzalutamide.
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MESH Headings
- Benzamides
- Benzopyrans/pharmacology
- Blotting, Western
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Cell Survival/physiology
- Drug Synergism
- Drug Therapy, Combination
- Humans
- Male
- Monosaccharides/pharmacology
- Nitriles
- Phenylthiohydantoin/analogs & derivatives
- Phenylthiohydantoin/pharmacology
- Phosphorylation
- Prostatic Neoplasms, Castration-Resistant/drug therapy
- Prostatic Neoplasms, Castration-Resistant/metabolism
- RNA, Neoplasm/chemistry
- RNA, Neoplasm/genetics
- RNA, Small Interfering/pharmacology
- Real-Time Polymerase Chain Reaction
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Ribosomal Protein S6 Kinases, 90-kDa/antagonists & inhibitors
- Ribosomal Protein S6 Kinases, 90-kDa/genetics
- Ribosomal Protein S6 Kinases, 90-kDa/metabolism
- Signal Transduction/drug effects
- Y-Box-Binding Protein 1/antagonists & inhibitors
- Y-Box-Binding Protein 1/genetics
- Y-Box-Binding Protein 1/metabolism
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22
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Targeting ribosomal S6 kinases/Y-box binding protein-1 signaling improves cellular sensitivity to taxane in prostate cancer. Prostate 2014; 74:829-38. [PMID: 24729449 DOI: 10.1002/pros.22799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/18/2014] [Indexed: 01/26/2023]
Abstract
BACKGROUND Taxanes are the only cytotoxic chemotherapeutic agents proved to prolong the survival in patients with castration-resistant prostate cancer. However, because of intrinsic and acquired resistances to taxanes, their therapeutical efficiencies are modest, bringing only a few months of survival benefit. Y-box binding protein-1 (YB-1) promotes cancer cell resistance to various anticancer treatments, including taxanes. Here, we aimed to elucidate the mechanism of taxane resistance by YB-1 and examined overcoming resistance by targeting YB-1 signaling. METHODS Gene and protein expression levels were evaluated by quantitative real-time polymerase chain reaction and Western blot analysis, respectively. We evaluated the sensitivity of prostate cancer cells to taxanes using cytotoxicity assays. RESULTS Natural taxane paclitaxel from Taxus brevifolia activated the Raf-1/extracellular signal-regulated kinase (ERK) pathway, leading to an activation of ribosomal S6 kinases (RSK)/YB-1 signaling. Activated Raf-1/ERK pathway was blunted by YB-1 knockdown in prostate cancer cells, indicating regulation between Raf-1/ERK signaling and YB-1. In addition, ERK or RSK was activated in taxane-resistant prostate cancer cells, resulting in YB-1 activation. YB-1 knockdown as well as RSK inhibition using RSK-specific siRNA or the small molecule inhibitor SL0101 successfully blocked activation of YB-1, leading to suppression of prostate cancer growth and sensitization to paclitaxel. CONCLUSIONS Taken together, these findings indicate that RSK/YB-1 signaling contributes to taxane resistance, and implicate the therapeutics targeting RSK/YB-1 signaling such as RSK inhibitor as a promising novel therapy against prostate cancer, especially in combination with taxane.
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23
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MP24-06 INTERACTION BETWEEN DOCETAXEL RESISTANCE AND CASTRATION RESISTANCE IN PROSTATE CANCER: IMPLICATIONS OF TWIST1, YB-1 AND ANDROGEN RECEPTOR. J Urol 2014. [DOI: 10.1016/j.juro.2014.02.287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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24
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Largen: A Molecular Regulator of Mammalian Cell Size Control. Mol Cell 2014; 53:904-15. [DOI: 10.1016/j.molcel.2014.02.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 11/26/2013] [Accepted: 02/13/2014] [Indexed: 12/31/2022]
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25
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Mule/Huwe1/Arf-BP1 suppresses Ras-driven tumorigenesis by preventing c-Myc/Miz1-mediated down-regulation of p21 and p15. Genes Dev 2013; 27:1101-14. [PMID: 23699408 DOI: 10.1101/gad.214577.113] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Tumorigenesis results from dysregulation of oncogenes and tumor suppressors that influence cellular proliferation, differentiation, apoptosis, and/or senescence. Many gene products involved in these processes are substrates of the E3 ubiquitin ligase Mule/Huwe1/Arf-BP1 (Mule), but whether Mule acts as an oncogene or tumor suppressor in vivo remains controversial. We generated K14Cre;Mule(flox/flox(y)) (Mule kKO) mice and subjected them to DMBA/PMA-induced skin carcinogenesis, which depends on oncogenic Ras signaling. Mule deficiency resulted in increased penetrance, number, and severity of skin tumors, which could be reversed by concomitant genetic knockout of c-Myc but not by knockout of p53 or p19Arf. Notably, in the absence of Mule, c-Myc/Miz1 transcriptional complexes accumulated, and levels of p21CDKN1A (p21) and p15INK4B (p15) were down-regulated. In vitro, Mule-deficient primary keratinocytes exhibited increased proliferation that could be reversed by Miz1 knockdown. Transfer of Mule-deficient transformed cells to nude mice resulted in enhanced tumor growth that again could be abrogated by Miz1 knockdown. Our data demonstrate in vivo that Mule suppresses Ras-mediated tumorigenesis by preventing an accumulation of c-Myc/Miz1 complexes that mediates p21 and p15 down-regulation.
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26
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Abstract
Androgen receptor (AR) signaling is critical for the tumorigenesis and development of prostate cancer, as well as the progression to castration-resistant prostate cancer. We previously showed that the heterochromatin protein 1 (HP1) β isoform plays a critical role in transactivation of AR signaling as an AR coactivator that promotes prostate cancer cell proliferation. However, the roles of other HP1 isoforms, HP1α and HP1γ, in AR expression and prostate cancer remain unclear. Here, we found that knockdown of HP1γ, but not HP1α, reduced AR expression and cell proliferation by inducing cell cycle arrest at G1 phase in LNCaP cells. Conversely, overexpression of full-length HP1α and its C-terminal deletion mutant increased AR expression and cell growth, whereas overexpression of HP1γ had no effect. Similarly, HP1α overexpression promoted 22Rv1 cell growth, whereas HP1γ knockdown reduced the proliferation of CxR cells, a castration-resistant LNCaP derivative. Taken together, HP1 isoforms distinctly augment AR signaling and cell growth in prostate cancer. Therefore, silencing of HP1β and HP1γ may be a promising therapeutic strategy for treatment of prostate cancer.
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27
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Prostaglandin receptor EP3 mediates growth inhibitory effect of aspirin through androgen receptor and contributes to castration resistance in prostate cancer cells. Endocr Relat Cancer 2013; 20:431-41. [PMID: 23493387 DOI: 10.1530/erc-12-0344] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although numerous epidemiological studies show aspirin to reduce risk of prostate cancer, the mechanism of this effect is unclear. Here, we first confirmed that aspirin downregulated androgen receptor (AR) and prostate-specific antigen in prostate cancer cells. We also found that aspirin upregulated prostaglandin receptor subtype EP3 but not EP2 or EP4. The EP3 antagonist L798106 and EP3 knockdown increased AR expression and cell proliferation, whereas the EP3 agonist sulprostone decreased them, indicating that EP3 affects AR expression. Additionally, EP3 (PTGER3) transcript levels were significantly decreased in human prostate cancer tissues compared with those in normal human prostate tissues, suggesting that EP3 is important to prostate carcinogenesis. Decreased EP3 expression was also seen in castration-resistant subtype CxR cells compared with parental LNCaP cells. Finally, we found that aspirin and EP3 modulators affected prostate cancer cell growth. Taken together, aspirin suppressed LNCaP cell proliferation via EP3 signaling activation; EP3 downregulation contributed to prostate carcinogenesis and to progression from androgen-dependent prostate cancer to castration-resistant prostate cancer by regulating AR expression. In conclusion, cyclooxygenases and EP3 may represent attractive therapeutic molecular targets in androgen-dependent prostate cancer.
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28
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YB-1 suppression induces STAT3 proteolysis and sensitizes renal cancer to interferon-α. Cancer Immunol Immunother 2013; 62:517-27. [PMID: 23052245 PMCID: PMC11029031 DOI: 10.1007/s00262-012-1356-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 09/17/2012] [Indexed: 01/15/2023]
Abstract
Renal cell carcinoma (RCC) accounts for 80-95 % of kidney tumors, and approximately 30 % of RCC patients have metastatic disease at diagnosis. Conventional chemotherapy is not effective in patients with metastatic RCC (MRCC); therefore, immunotherapy with interferon-α (IFN-α) has been employed to improve survival. However, the response rate of MRCC to IFN-α therapy is low. We previously reported that a signal transducer and activator 3 (STAT3) polymorphism was a useful diagnostic marker to predict the response to IFN-α therapy in patients with MRCC. Therefore, we hypothesized the inhibition of STAT3 in the addition of IFN-α therapy might be useful. Moreover, the blockage of STAT3 itself has been reported to enhance the antitumor effects. However, because IFN-α is thought to elicit its therapeutic effect via enhancement of an antitumor immune response mediated by lymphocytes that can be activated by IFN-α administrations, it is probable that the suppression of STAT3 in vivo relates to autoimmune disorders. In the present study, we found Y-box binding protein-1 (YB-1) was poorly expressed in T lymphocytes, as compared with cancer tissues. YB-1 was reported to have an important effect on the STAT3 pathway. Suppression of STAT3 by YB-1 inhibition did not seem to enhance the potential risk for autoimmune disorders. Moreover, we found sensitivity to IFN-α was increased by YB-1 suppression, and this suppression did not down-regulate IFN-α activation of T lymphocytes.
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29
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D-2-hydroxyglutarate produced by mutant IDH1 perturbs collagen maturation and basement membrane function. Genes Dev 2012; 26:2038-49. [PMID: 22925884 DOI: 10.1101/gad.198200.112] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Isocitrate dehydrogenase-1 (IDH1) R132 mutations occur in glioma, but their physiological significance is unknown. Here we describe the generation and characterization of brain-specific Idh1 R132H conditional knock-in (KI) mice. Idh1 mutation results in hemorrhage and perinatal lethality. Surprisingly, intracellular reactive oxygen species (ROS) are attenuated in Idh1-KI brain cells despite an apparent increase in the NADP(+)/NADPH ratio. Idh1-KI cells also show high levels of D-2-hydroxyglutarate (D2HG) that are associated with inhibited prolyl-hydroxylation of hypoxia-inducible transcription factor-1α (Hif1α) and up-regulated Hif1α target gene transcription. Intriguingly, D2HG also blocks prolyl-hydroxylation of collagen, causing a defect in collagen protein maturation. An endoplasmic reticulum (ER) stress response induced by the accumulation of immature collagens may account for the embryonic lethality of these mutants. Importantly, D2HG-mediated impairment of collagen maturation also led to basement membrane (BM) aberrations that could play a part in glioma progression. Our study presents strong in vivo evidence that the D2HG produced by the mutant Idh1 enzyme is responsible for the above effects.
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30
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Downregulation of phosphodiesterase 4B (PDE4B) activates protein kinase A and contributes to the progression of prostate cancer. Prostate 2012; 72:741-51. [PMID: 22529021 DOI: 10.1002/pros.21478] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 07/29/2011] [Indexed: 11/05/2022]
Abstract
BACKGROUND Prostate cancer is the most commonly diagnosed non-cutaneous cancer in American men. Unfortunately, few successful therapies for castration-resistant prostate cancer (CRPC) exist. The protein kinase A (PKA) pathway is a critical mediator of cellular proliferation and differentiation in various normal and cancerous cells. However, the PKA activity and the mechanism of regulation in CRPC remain unclear. Then, in this study, we intended to reveal the PKA activity and the mechanism of regulation in CRPC. METHODS Western blotting, quantitative real-time polymerase chain reaction, cytotoxicity analysis, and cell proliferation assay were used to resolve the regulatory role of PKA in prostate cancer cell line, LNCaP and their derivatives. RESULTS cAMP-specific phosphodiesterase 4B (PDE4B) was downregulated and the PKA pathway was activated in castration-resistant LNCaP derivatives (CxR cells). Rolipram activated the PKA pathway via inhibition of PDE4B, resulting in AR transactivation while the PKA inhibitor, H89 reduced AR transactivation. In response to hydrogen peroxide and in hydrogen peroxide-resistant LNCaP derivatives (HPR50 cells) PDE4B was decreased and as a result PKA activity was increased. Moreover, PDE4B expression was reduced in advanced prostate cancer and PDE4B knockdown promoted castration-resistant growth of LNCaP cells. CONCLUSIONS Oxidative stress may suppress PDE4B expression and activate the PKA pathway. The PDE4B/PKA pathway contributed to progression of androgen-dependent prostate cancer to CRPC. This pathway may represent an attractive therapeutic molecular target.
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31
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Sunitinib enhances antitumor effects against chemotherapy-resistant bladder cancer through suppression of ERK1/2 phosphorylation. Int J Oncol 2012; 40:1691-6. [PMID: 22344606 DOI: 10.3892/ijo.2012.1368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 12/12/2011] [Indexed: 11/06/2022] Open
Abstract
Bladder cancer patients who are refractory to chemotherapy have a poor prognosis. Furthermore, additional chemotherapies provide little benefit to patients who have relapsed after an initial response. Recently, it was reported that several molecular pathways are implicated in bladder carcinogenesis, including the epidermal growth factor receptor (EGFR) pathway, the vascular endothelial growth factor (VEGF) pathway and the Ras-MAPK pathway. We hypothesized that sunitinib would be effective in bladder cancer as it is an oral inhibitor of multiple receptor tyrosine kinases, including VEGF receptors, platelet derived growth factor (PDGF) receptors and stem cell factor receptor (c-KIT), and is a standard first-line treatment of advanced clear cell renal carcinoma. In the present study, the antiproliferative effects of sunitinib were clearly demonstrated in KK47, KK47/DDP20 and KK47/ADR cell lines in vitro due to the suppression of ERK1/2 phosphorylation. In a mouse model, the antitumor effects of sunitinib were again clearly seen. Also, treatment with sunitinib decreased the abundance of regulatory T cells (Tregs). However, cytotoxic T lymphocyte (CTL) activity was not induced sufficiently as compared with an IFN-α-treated group. Our results suggested that sunitinib was effective in chemotherapy-resistant bladder cancer patients. On the other hand, these findings provided the rationale for combination therapy with sunitinib and immune-based cancer therapy for advanced malignancies to prevent the occurrence of rebound phenomena.
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32
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33
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Sensitivity of doxorubicin-resistant cells to sorafenib: possible role for inhibition of eukaryotic initiation factor-2alpha phosphorylation. Int J Oncol 2010; 37:509-17. [PMID: 20596679 DOI: 10.3892/ijo_00000700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Patients with advanced cancer including breast cancer, hepatocellular cancer and urothelial cancer frequently receive a chemotherapy regimen containing doxorubicin. However, doxorubicin-resistance is a major obstacle for cancer chemotherapy. Recently, several molecular-targeted agents have become available. Sorafenib (BAY 43-9006) is known to target multiple kinases and has demonstrated activity in renal cell and hepatocellular cancer. In this study, sorafenib was found to inhibit phosphorylation of the eukaryotic initiation factor-2alpha (eIF2alpha), induce cell cycle arrest at G2 phase and increase cellular apoptosis in doxorubicin-resistant human urothelial cell lines. An eIF2alpha kinase, PERK was responsible for eIF2alpha phosphorylation and PERK knockdown induced cellular apoptosis similar to sorafenib treatment in doxorubicin-resistant cancer cells. Furthermore, sorafenib sensitized doxorubicin-resistant cancer cells, but not their parental cells to oxidative stress exerted by both hydrogen peroxide and doxorubicin. In addition, PERK knockdown sensitized doxorubicin-resistant cancer cells to oxidative stress. In conclusion, PERK inhibition using sorafenib with or without doxorubicin might be a promising therapeutic approach for doxorubicin-resistant cancers retaining high phosphorylation levels of eIF2alpha.
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34
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Dual specificity phosphatase16 is a negative regulator of c-Jun NH2-terminal kinase activity in T cells. Microbiol Immunol 2010; 54:105-11. [PMID: 20377744 DOI: 10.1111/j.1348-0421.2009.00188.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Activation of MAPK is negatively regulated by DUSP, which dephosphorylate the phosphothreonine and phosphotyrosine residues. We have identified a novel JNK-specific DUSP, DUSP16, from murine macrophages. Its involvement in T cells has not yet been defined. In the present study, we found expression of DUSP16 in thymocytes and activated T cells but not in naive T cells. To elucidate the roles of DUSP16 in T cells, transgenic mice expressing a dominant negative form of DUSP16 specifically in T cells were generated (dnDUSP16 Tg). JNK activity was selectively augmented in the thymocytes of these dnDUSP16 Tg mice. CD4 T cells in dnDUSP16 Tg mice showed normal levels of proliferation and IL-2 production after TCR triggering, while they produced increased IFN-gamma but reduced Th2 cytokines compared with wild type CD4 T cells. On the other hand CD8 T cells in dnDUSP16 Tg mice produced an increased amount of IL-2, which resulted in enhanced proliferation and IFN-gamma production. These results suggest that DUSP16 is an important regulator of JNK activity and effector functions of CD4 and CD8 T cells.
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35
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Tyrosine Kinase 2 Plays Critical Roles in the Pathogenic CD4 T Cell Responses for the Development of Experimental Autoimmune Encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2009; 183:7539-46. [DOI: 10.4049/jimmunol.0902740] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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36
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IL-15 is critical for the maintenance and innate functions of self-specific CD8(+) T cells. Eur J Immunol 2009; 39:1784-93. [PMID: 19544306 DOI: 10.1002/eji.200839106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
IL-15 is a pleiotropic cytokine involved in host defense as well as autoimmunity. IL-15-deficient mice show a decrease of memory phenotype (MP) CD8(+) T cells, which develop naturally in naïve mice and whose origin is unclear. It has been shown that self-specific CD8(+) T cells developed in male H-Y antigen-specific TCR transgenic mice share many similarities with naturally occurring MP CD8(+) T cells in normal mice. In this study, we found that H-Y antigen-specific CD8(+) T cells in male but not female mice decreased when they were crossed with IL-15-deficient mice, mainly due to impaired peripheral maintenance. The self-specific TCR transgenic CD8(+) T cells developed in IL-15-deficient mice showed altered surface phenotypes and reduced effector functions ex vivo. Bystander activation of the self-specific CD8(+) T cells was induced in vivo during infection with Listeria monocytogenes, in which proliferation but not IFN-gamma production was IL-15-dependent. These results indicated important roles for IL-15 in the maintenance and functions of self-specific CD8(+) T cells, which may be included in the naturally occurring MP CD8(+) T-cell population in naïve normal mice and participate in innate host defense responses.
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37
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Identification of CD25+ gamma delta T cells as fetal thymus-derived naturally occurring IL-17 producers. THE JOURNAL OF IMMUNOLOGY 2009; 181:5940-7. [PMID: 18941182 DOI: 10.4049/jimmunol.181.9.5940] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We previously reported that resident gammadelta T cells in the peritoneal cavity rapidly produced IL-17 in response to Escherichia coli infection to mobilize neutrophils. We found in this study that the IL-17-producing gammadelta T cells did not produce IFN-gamma or IL-4, similar to Th17 cells. IL-17-producing gammadelta T cells specifically express CD25 but not CD122, whereas CD122(+) gammadelta T cells produced IFN-gamma. IL-17-producing gammadelta T cells were decreased but still present in IL-2- or CD25-deficient mice, suggesting a role of IL-2 for their maintenance. IFN-gamma-producing CD122(+) gammadelta T cells were selectively decreased in IL-15-deficient mice. Surprisingly, IL-17-producing gammadelta T cells were already detected in the thymus, although CD25 was not expressed on the intrathymic IL-17-producing gammadelta T cells. The number of thymic IL-17-producing gammadelta T cells was peaked at perinatal period and decreased thereafter, coincided with the developmental kinetics of Vgamma6(+) Vdelta1(+) gammadelta T cells. The number of IL-17-producing gammadelta T cells was decreased in fetal thymus of Vdelta1-deficient mice, whereas Vgamma5(+) fetal thymocytes in normal mice did not produce IL-17. Thus, it was revealed that the fetal thymus-derived Vgamma6(+) Vdelta1(+) T cells functionally differentiate to produce IL-17 within thymus and thereafter express CD25 to be maintained in the periphery.
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