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Li R, Wang R, Zhai R, Dong Z. Targeted Inhibition of Mammalian Target of Rapamycin (mTOR) Signaling Pathway Inhibits Proliferation and Induces Apoptosis of Laryngeal Carcinoma Cells in vitro. TUMORI JOURNAL 2018; 97:781-6. [DOI: 10.1177/030089161109700616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aim and Objective Laryngeal carcinoma is one of the most aggressive cancers of the head and neck region. The survival rate of patients with laryngeal carcinoma is low due to its late metastases and resistance to chemotherapy and radiotherapy. It was reported that mTOR was involved in the growth and apoptosis of various cancer cells. The aim of this study was to detect the effects of mTOR inhibition by mTOR shRNA on the proliferation, apoptosis and invasive ability of Hep-2 human laryngeal carcinoma cells in vitro. Methods and Study Design mTOR shRNA was designed and transfected into Hep-2 human laryngeal carcinoma cells. Untreated cells and cells treated with control vector (non-targeted shRNA) were used as control. The proliferation and apoptosis of Hep-2 cells were detected by MTT and flow cytometry. A transwell assay was used to measure the invasive ability of Hep-2. The inhibition effects on the mTOR signaling pathway by mTOR shRNA were studied using RT-PCR and Western blot. Results Our results showed that the mRNA and protein expression of mTOR and Akt were high in laryngeal carcinoma cells and could be inhibited by mTOR shRNA. At the same time, low expression of PTEN mRNA and protein was observed in Hep-2 cells. The expression increased when the cells were transfected with mTOR shRNA. This showed that mTOR shRNA could inhibit the proliferation and invasive ability of Hep-2 cells. It also could induce the apoptosis of Hep-2 cells in vitro. Conclusions The mTOR signaling pathway plays an important role in the development of laryngeal carcinoma. The mTOR shRNA we designed in this experiment effectively inhibited the mTOR signaling pathway. It inhibited the proliferation and invasive ability of the studied laryngeal carcinoma cells and induced their apoptosis in vitro. mTOR might therefore be a useful target in the therapy of laryngeal carcinoma.
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Affiliation(s)
- Rongrui Li
- Department of Otorhinolaryngology & Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun
- Department of Orthopedic Surgery, the First Affiliated Hospital of JiaMuSi University, Heilongjiang, China
| | - Riguang Wang
- Department of Orthopedic Surgery, the First Affiliated Hospital of JiaMuSi University, Heilongjiang, China
| | - Raosheng Zhai
- Department of Orthopedic Surgery, the First Affiliated Hospital of JiaMuSi University, Heilongjiang, China
| | - Zhen Dong
- Department of Otorhinolaryngology & Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun
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2
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White MA, Lin C, Rajapakshe K, Dong J, Shi Y, Tsouko E, Mukhopadhyay R, Jasso D, Dawood W, Coarfa C, Frigo DE. Glutamine Transporters Are Targets of Multiple Oncogenic Signaling Pathways in Prostate Cancer. Mol Cancer Res 2017; 15:1017-1028. [PMID: 28507054 DOI: 10.1158/1541-7786.mcr-16-0480] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/11/2017] [Accepted: 05/09/2017] [Indexed: 01/07/2023]
Abstract
Despite the known importance of androgen receptor (AR) signaling in prostate cancer, the processes downstream of AR that drive disease development and progression remain poorly understood. This knowledge gap has thus limited the ability to treat cancer. Here, it is demonstrated that androgens increase the metabolism of glutamine in prostate cancer cells. This metabolism was required for maximal cell growth under conditions of serum starvation. Mechanistically, AR signaling promoted glutamine metabolism by increasing the expression of the glutamine transporters SLC1A4 and SLC1A5, genes commonly overexpressed in prostate cancer. Correspondingly, gene expression signatures of AR activity correlated with SLC1A4 and SLC1A5 mRNA levels in clinical cohorts. Interestingly, MYC, a canonical oncogene in prostate cancer and previously described master regulator of glutamine metabolism, was only a context-dependent regulator of SLC1A4 and SLC1A5 levels, being unable to regulate either transporter in PTEN wild-type cells. In contrast, rapamycin was able to decrease the androgen-mediated expression of SLC1A4 and SLC1A5 independent of PTEN status, indicating that mTOR complex 1 (mTORC1) was needed for maximal AR-mediated glutamine uptake and prostate cancer cell growth. Taken together, these data indicate that three well-established oncogenic drivers (AR, MYC, and mTOR) function by converging to collectively increase the expression of glutamine transporters, thereby promoting glutamine uptake and subsequent prostate cancer cell growth.Implications: AR, MYC, and mTOR converge to increase glutamine uptake and metabolism in prostate cancer through increasing the levels of glutamine transporters. Mol Cancer Res; 15(8); 1017-28. ©2017 AACR.
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Affiliation(s)
- Mark A White
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Chenchu Lin
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Kimal Rajapakshe
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Jianrong Dong
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Yan Shi
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Efrosini Tsouko
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Ratna Mukhopadhyay
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Diana Jasso
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Wajahat Dawood
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Daniel E Frigo
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas. .,Molecular Medicine Program, The Houston Methodist Research Institute, Houston, Texas
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3
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Advanced gynecologic malignancies treated with a combination of the VEGF inhibitor bevacizumab and the mTOR inhibitor temsirolimus. Oncotarget 2015; 5:1846-55. [PMID: 24742900 PMCID: PMC4039109 DOI: 10.18632/oncotarget.1834] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background: Bevacizumab and temsirolimus are active agents in gynecologic tumors. Temsirolimus attenuates upregulation of HIF-1α levels, a resistance mechanism for antiangiogenics, and targets the PI3-kinase/AKT/mTOR axis, commonly aberrant in these tumors Patients and Methods: We analyzed safety and responses in 41 patients with gynecologic cancers treated as part of a Phase I study of bevacizumab and temsirolimus. Results: Median age of the 41 women was 60 years (range, 33-80 years); median number of prior systemic therapies was 4 (1-11). Grade 3 or 4 treatment-related toxicities included: thrombocytopenia (10%), mucositis (2%), hypertension (2%), hypercholesterolemia (2%), fatigue (7%), elevated aspartate aminotransferase (2%), and neutropenia (2%). Twenty-nine patients (71%) experienced no treatment-related toxicity greater than grade 2. Full FDA-approved doses of both drugs (bevacizumab 15mg/kg IV Q3weeks and temsirolimus 25mg IV weekly) were administered without dose-limiting toxicity. Eight patients (20%) achieved stable disease (SD) ≥ 6 months and 7 patients (17%), a partial response (PR) [total = 15/41 patients (37%)]. Eight of 13 patients (62%) with high-grade serous histology (ovarian or primary peritoneal) achieved SD ≥ 6 months/PR. Conclusion: Bevacizumab and temsirolimus was well tolerated. Thirty-seven percent of heavily-pretreated patients achieved SD ≥ 6 months/PR, suggesting that this combination warrants further study.
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Afonso J, Longatto-Filho A, DA Silva VM, Amaro T, Santos LL. Phospho-mTOR in non-tumour and tumour bladder urothelium: Pattern of expression and impact on urothelial bladder cancer patients. Oncol Lett 2014; 8:1447-1454. [PMID: 25202348 PMCID: PMC4156165 DOI: 10.3892/ol.2014.2392] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 06/24/2014] [Indexed: 12/28/2022] Open
Abstract
Urothelial bladder carcinoma (UBC) is heterogeneous in its pathology and clinical behaviour. Evaluation of prognostic and predictive biomarkers is necessary, in order to produce personalised treatment options. The present study used immunohistochemistry to evaluate UBC sections containing tumour and non-tumour areas from 76 patients, for the detection of p-mTOR, CD31 and D2-40 (blood and lymphatic vessels identification, respectively). Of the non-tumour and tumour sections, 36 and 20% were scored positive for p-mTOR expression, respectively. Immunoexpression was observed in umbrella cells from non-tumour urothelium, in all cell layers from non-muscle-invasive (NMI) tumours (including expression in superficial cells), and in spots of cells from muscle-invasive (MI) tumours. Positive expression decreased from non-tumour to tumour urothelium, and from pT1/pTis to pT3/pT4 tumours; however, the few pT3/pT4 positive cases had worse survival rates, with 5-year disease-free survival being significantly lower. Angiogenesis occurrence was impaired in pT3/pT4 tumours that did not express p-mTOR. In conclusion, p-mTOR expression in non-tumour umbrella cells is likely a reflection of their metabolic plasticity, and extension to the inner layers of the urothelium in NMI tumours is consistent with an enhanced malignant potential. The expression in cell spots in a few MI tumours and absence of expression in the remaining tumours is intriguing and requires further research. Additional studies regarding the up- and downstream effectors of the mTOR pathway should be conducted.
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Affiliation(s)
- Julieta Afonso
- Life and Health Sciences Research Institute (ICVS), School of Healh Sciences (ECS) University of Minho, Braga 4710-057, Portugal ; ICVS/3B's, PT Government Associate Laboratory, Braga 4710-057/Guimarães 4806-909, Portugal
| | - Adhemar Longatto-Filho
- Life and Health Sciences Research Institute (ICVS), School of Healh Sciences (ECS) University of Minho, Braga 4710-057, Portugal ; ICVS/3B's, PT Government Associate Laboratory, Braga 4710-057/Guimarães 4806-909, Portugal ; Laboratory of Medical Investigation (LIM 14), Faculty of Medicine, São Paulo State University, São Paulo 01246-000, Brazil ; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo 14784-400, Brazil
| | | | - Teresina Amaro
- Experimental Pathology and Therapeutics Research Center, Portuguese Institute of Oncology (IPO), Porto 4200-072, Portugal
| | - Lúcio L Santos
- Department of Surgical Oncology, Portuguese Institute of Oncology (IPO), Porto 4200-072, Portugal ; Faculty of Health Sciences, University Fernando Pessoa, Porto 4200-150, Portugal
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Tsouko E, Khan AS, White MA, Han JJ, Shi Y, Merchant FA, Sharpe MA, Xin L, Frigo DE. Regulation of the pentose phosphate pathway by an androgen receptor-mTOR-mediated mechanism and its role in prostate cancer cell growth. Oncogenesis 2014; 3:e103. [PMID: 24861463 PMCID: PMC4035695 DOI: 10.1038/oncsis.2014.18] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 04/23/2014] [Indexed: 12/11/2022] Open
Abstract
Cancer cells display an increased demand for glucose. Therefore, identifying the specific aspects of glucose metabolism that are involved in the pathogenesis of cancer may uncover novel therapeutic nodes. Recently, there has been a renewed interest in the role of the pentose phosphate pathway in cancer. This metabolic pathway is advantageous for rapidly growing cells because it provides nucleotide precursors and helps regenerate the reducing agent NADPH, which can contribute to reactive oxygen species (ROS) scavenging. Correspondingly, clinical data suggest glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, is upregulated in prostate cancer. We hypothesized that androgen receptor (AR) signaling, which plays an essential role in the disease, mediated prostate cancer cell growth in part by increasing flux through the pentose phosphate pathway. Here, we determined that G6PD, NADPH and ribose synthesis were all increased by AR signaling. Further, this process was necessary to modulate ROS levels. Pharmacological or molecular inhibition of G6PD abolished these effects and blocked androgen-mediated cell growth. Mechanistically, regulation of G6PD via AR in both hormone-sensitive and castration-resistant models of prostate cancer was abolished following rapamycin treatment, indicating that AR increased flux through the pentose phosphate pathway by the mammalian target of rapamycin (mTOR)-mediated upregulation of G6PD. Accordingly, in two separate mouse models of Pten deletion/elevated mTOR signaling, Pb-Cre;Pten(f/f) and K8-CreER(T2);Pten(f/f), G6PD levels correlated with prostate cancer progression in vivo. Importantly, G6PD levels remained high during progression to castration-resistant prostate cancer. Taken together, our data suggest that AR signaling can promote prostate cancer through the upregulation of G6PD and therefore, the flux of sugars through the pentose phosphate pathway. Hence, these findings support a vital role for other metabolic pathways (that is, not glycolysis) in prostate cancer cell growth and maintenance.
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Affiliation(s)
- E Tsouko
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - A S Khan
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - M A White
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - J J Han
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Y Shi
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - F A Merchant
- Department of Engineering Technology, University of Houston, Houston, TX, USA
| | - M A Sharpe
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - L Xin
- 1] Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA [2] Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA [3] Dan L. Duncan Cancer Center, Houston, TX, USA
| | - D E Frigo
- 1] Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA [2] Center for Genomic Medicine, Houston Methodist Research Institute, Houston, TX, USA
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Kozakowski N, Hartmann C, Klingler HC, Susani M, Mazal PR, Scharrer A, Haitel A. Immunohistochemical expression of PDGFR, VEGF-C, and proteins of the mToR pathway before and after androgen deprivation therapy in prostate carcinoma: significant decrease after treatment. Target Oncol 2013; 9:359-66. [PMID: 24243494 DOI: 10.1007/s11523-013-0298-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 10/30/2013] [Indexed: 12/23/2022]
Abstract
Targeted therapy in hormone refractory prostate cancer (HRPC) is currently under evaluation in many trials. The effect of androgen deprivation therapy (ADT) on many targets in prostate cancer is incompletely known. For the first time, immunohistochemical expression of the platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR), vascular endothelial growth factor C (VEGF-C), mammalian target of rapamycin (mToR), p70 ribosomal protein S6 kinase 1 (PS6K), human epidermal growth factor receptor 2 (c-erbB-2), and carbonic anhydrase IX (CA9) was evaluated in 44 patients with prostate carcinoma treated with or without ADT, at biopsy time and after radical prostatectomy. PDGFR, VEGF-C, mToR, and PS6K expression was significantly reduced (p = 0.002, p = 0.035, p = 0.025, and p = 0.033, respectively) after ADT, whereas expression of EGFR, c-erbB-2, and CA9 was not influenced by ADT. In conclusion, targeting PDGFR, VEGF-C, mToR, or PS6K after ADT should be considered with precaution, as those targets can severely be altered or functionally deregulated by ADT.
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Affiliation(s)
- Nicolas Kozakowski
- Clinical Institute for Pathology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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7
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Sun MM, Zhang MZ, Chen Y, Li SL, Zhang W, Ya GW, Chen KS. Mechanistic target of rapamycin small interfering RNA and rapamycin synergistically inhibit tumour growth in a mouse xenograft model of human oesophageal carcinoma. J Int Med Res 2013. [PMID: 23206445 DOI: 10.1177/030006051204000502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES To investigate the effect of mechanistic target of rapamycin (mTOR)-specific small interfering RNA (siRNA) and rapamycin on tumour size and levels of hypoxia inducible factor 1α(HIF-1α), vascular endothelial growth factor (VEGF) and mTOR proteins, and mTOR mRNA, in a mouse xenograft model of human oesophageal carcinoma. METHODS Tumours were induced in BALB/c nude mice using the human oesophageal squamous cell carcinoma cell line, EC1, injected subcutaneously. Animals were divided into four treatment groups (n = 5 per group) after 7 days: control (phosphate buffered saline, daily intraperitoneal [i.p.] injection); 50 μg/kg rapamycin, daily i.p. injection; 3 μg/kg mTOR siRNA, daily i.p. injection; combined mTOR siRNA and rapamycin, daily i.p. injections. Tumour volume was measured 21 days after xenograft. Levels of mTOR, VEGF and HIF-1α were assessed via immunohistochemistry and in situ hybridization. RESULTS mTOR siRNA and/or rapamycin significantly decreased tumour volume and levels of HIF-1α, VEGF and mTOR protein, and mTOR mRNA. Combination treatment was significantly more effective than either treatment alone. CONCLUSIONS mTOR siRNA and/or rapamycin inhibited the growth of oesophageal carcinoma in vivo. This may represent a novel and effective treatment strategy for oesophageal carcinoma.
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Affiliation(s)
- M M Sun
- Department of Oncology, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
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Amato RJ, Wilding G, Bubley G, Loewy J, Haluska F, Gross ME. Safety and preliminary efficacy analysis of the mTOR inhibitor ridaforolimus in patients with taxane-treated, castration-resistant prostate cancer. Clin Genitourin Cancer 2012; 10:232-8. [PMID: 22695254 DOI: 10.1016/j.clgc.2012.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 04/17/2012] [Accepted: 05/03/2012] [Indexed: 01/12/2023]
Abstract
BACKGROUND Few options are available after taxane-based therapy in men with CRPC. Genetic alterations involving the mTOR pathway have been associated with CRPC development, raising the hypothesis that blocking mTOR signaling may be an effective targeted approach to treatment. PATIENTS AND METHODS In this open-label phase II study, the mTOR inhibitor Ridaforolimus was administered at a dose of 50 mg intravenous once weekly to 38 patients with taxane-treated CRPC. The primary end point was best overall response according to modified Response Evaluation Criteria in Solid Tumors guidelines. Serum prostate-specific antigen levels were prospectively monitored as a biomarker for cancer activity. RESULTS No objective responses were observed, but 18 patients (47.4%) had stable disease as their best response. Based on progression-free survival analysis, median time to progression with Ridaforolimus was 28 days (95% confidence interval, 27-29). Eight patients (21.1%) had stable disease as their best overall prostate-specific antigen response. The median number of days from first to last dose was 109.5 days (range, 1-442 days). Ridaforolimus was generally well tolerated, with a safety profile similar to that observed in patients with advanced malignancies. The most common side effects were typically mild or moderate in severity. CONCLUSIONS Ridaforolimus was generally well tolerated. Treatment did not produce objective responses, but stable disease was observed in some patients with taxane-treated CRPC. Alternative treatment regimens, such as combination therapy with a taxane or in a maintenance treatment paradigm, should be considered for further evaluation in this patient population.
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Affiliation(s)
- Robert J Amato
- The University of Texas Health Medical School, Memorial Hermann Cancer Center, Houston, USA.
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Feng W, Jia S. Rapamycin inhibits the invasive ability of thyroid cancer cells by down-regulating the expression of VEGF-C in vitro. Cell Biochem Funct 2012; 30:487-91. [PMID: 22447639 DOI: 10.1002/cbf.2824] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/28/2012] [Accepted: 03/01/2011] [Indexed: 01/01/2023]
Affiliation(s)
- Wenli Feng
- Department of Head and Neck Surgery, the Third Affiliated Hospital; Harbin Medical University; Harbin; 150081; Heilongjiang; China
| | - Shenshan Jia
- Department of Head and Neck Surgery, the Third Affiliated Hospital; Harbin Medical University; Harbin; 150081; Heilongjiang; China
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Ellis L, Lehet K, Ramakrishnan S, Adelaiye R, Miles KM, Wang D, Liu S, Atadja P, Carducci MA, Pili R. Concurrent HDAC and mTORC1 inhibition attenuate androgen receptor and hypoxia signaling associated with alterations in microRNA expression. PLoS One 2011; 6:e27178. [PMID: 22087262 PMCID: PMC3210144 DOI: 10.1371/journal.pone.0027178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 10/11/2011] [Indexed: 01/29/2023] Open
Abstract
Specific inhibitors towards Histone Deacetylases (HDACs) and Mammalian Target of Rapamycin Complex 1 (mTORC1) have been developed and demonstrate potential as treatments for patients with advanced and/or metastatic and castrate resistant prostate cancer (PCa). Further, deregulation of HDAC expression and mTORC1 activity are documented in PCa and provide rational targets to create new therapeutic strategies to treat PCa. Here we report the use of the c-Myc adenocarcinoma cell line from the c-Myc transgenic mouse with prostate cancer to evaluate the in vitro and in vivo anti-tumor activity of the combination of the HDAC inhibitor panobinostat with the mTORC1 inhibitor everolimus. Panobinostat/everolimus combination treatment resulted in significantly greater antitumor activity in mice bearing androgen sensitive Myc-CaP and castrate resistant Myc-CaP tumors compared to single treatments. We identified that panobinostat/everolimus combination resulted in enhanced anti-tumor activity mediated by decreased tumor growth concurrent with augmentation of p21 and p27 expression and the attenuation of angiogenesis and tumor proliferation via androgen receptor, c-Myc and HIF-1α signaling. Also, we observed altered expression of microRNAs associated with these three transcription factors. Overall, our results demonstrate that low dose concurrent panobinostat/everolimus combination therapy is well tolerated and results in greater anti-tumor activity compared to single treatments in tumor bearing immuno-competent mice. Finally, our results suggest that response of selected miRs could be utilized to monitor panobinostat/everolimus in vivo activity.
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Affiliation(s)
- Leigh Ellis
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
| | - Kristin Lehet
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
| | - Swathi Ramakrishnan
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
| | - Remi Adelaiye
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
| | - Kiersten M. Miles
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
| | - Dan Wang
- Roswell Park Cancer Institute, Department of Bioinformatics, Buffalo, New York, United States of America
| | - Song Liu
- Roswell Park Cancer Institute, Department of Bioinformatics, Buffalo, New York, United States of America
| | - Peter Atadja
- Novartis Biomedical Research Institute, Shanghai, China
| | - Michael A. Carducci
- The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Roberto Pili
- Roswell Park Cancer Institute, Genitourinary Program, Grace Cancer Drug Center, Buffalo, New York, United States of America
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Regulation of androgen receptor-mediated transcription by RPB5 binding protein URI/RMP. Mol Cell Biol 2011; 31:3639-52. [PMID: 21730289 DOI: 10.1128/mcb.05429-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Androgen receptor (AR)-mediated transcription is modulated by interaction with coregulatory proteins. We demonstrate that the unconventional prefoldin RPB5 interactor (URI) is a new regulator of AR transcription and is critical for antagonist (bicalutamide) action. URI is phosphorylated upon androgen treatment, suggesting communication between the URI and AR signaling pathways. Whereas depletion of URI enhances AR-mediated gene transcription, overexpression of URI suppresses AR transcriptional activation and anchorage-independent prostate cancer cell growth. Repression of AR-mediated transcription is achieved, in part, by URI binding and regulation of androgen receptor trapped clone 27 (Art-27), a previously characterized AR corepressor. Consistent with this idea, genome-wide expression profiling in prostate cancer cells upon depletion of URI or Art-27 reveals substantially overlapping patterns of gene expression. Further, depletion of URI increases the expression of the AR target gene NKX-3.1, decreases the recruitment of Art-27, and increases AR occupancy at the NKX-3.1 promoter. While Art-27 can bind AR directly, URI is bound to chromatin prior to hormone-dependent recruitment of AR, suggesting a role for URI in modulating AR recruitment to target genes.
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Gaudet M, Remtulla N, Jackson SE, Main ERG, Bracewell DG, Aeppli G, Dalby PA. Protein denaturation and protein:drugs interactions from intrinsic protein fluorescence measurements at the nanolitre scale. Protein Sci 2010; 19:1544-54. [PMID: 20552687 DOI: 10.1002/pro.433] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein stability and ligand-binding affinity measurements are widely required for the formulation of biopharmaceutical proteins, protein engineering and drug screening within life science research. Current techniques either consume too much of often precious biological or compound materials, in large sample volumes, or alternatively require chemical labeling with fluorescent tags to achieve measurements at submicrolitre volumes with less sample. Here we present a quantitative and accurate method for the determination of protein stability and the affinity for small molecules, at only 1.5-20 nL optical sample volumes without the need for fluorescent labeling, and that takes advantage of the intrinsic tryptophan fluorescence of most proteins. Coupled to appropriate microfluidic sample preparation methods, the sample requirements could thus be reduced 85,000-fold to just 10(8) molecules. The stability of wild-type FKBP-12 and a destabilizing binding-pocket mutant are studied in the presence and absence of rapamycin, to demonstrate the potential of the technique to both drug screening and protein engineering. The results show that 75% of the interaction energy between FKBP-12 and rapamycin originates from residue Phe99 in the binding site.
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Affiliation(s)
- Matthieu Gaudet
- Department of Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
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