1
|
Rashid M, Zadeh LR, Baradaran B, Molavi O, Ghesmati Z, Sabzichi M, Ramezani F. Up-down regulation of HIF-1α in cancer progression. Gene 2021; 798:145796. [PMID: 34175393 DOI: 10.1016/j.gene.2021.145796] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/25/2021] [Accepted: 06/22/2021] [Indexed: 12/19/2022]
Abstract
Hypoxia induicible factor-1 alpha (HIF-1α) is a key transcription factor in cancer progression and target therapy in cancer. HIF-1α acts differently depending on presence or absence of Oxygen. In an oxygen-immersed environment, HIF-1α completely deactivated and destroyed by the ubiquitin proteasome pathway (UPP). In contrast, in the oxygen-free environment, it escapes destruction and enters to the nucleus of cells then upregulates many genes involved in cancer progression. Overexpressed HIF-1α and downstream genes support cancer progression through various mechanisms including angiogenesis, proliferation and survival of cells, metabolism reprogramming, invasion and metastasis, cancer stem cell maintenance, induction of genetic instability, and treatment resistance. HIF-1α can be provoked by signaling pathways unrelated to hypoxia during cancer progression. Therefore, cancer development and progression can be modulated by targeting HIF-1α and its downstream signaling molecules. In this regard, HIF-1α inhibitors which are categorized into the agents that regulate HIF-1α in gene, mRNA and protein levels used as an efficient way in cancer treatment. Also, HIF-1α expression can be negatively affected by the agents suppressing the activation of mTOR, PI3k/Akt and MAPK pathways.
Collapse
Affiliation(s)
- Mohsen Rashid
- Department of Molecular Medicine, School of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leila Rostami Zadeh
- Department of Molecular Medicine, School of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behzad Baradaran
- Department of Molecular Medicine, School of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ommoleila Molavi
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Zeinab Ghesmati
- Department of Medical Biotechnology, School of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehdi Sabzichi
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Fatemeh Ramezani
- Department of Molecular Medicine, School of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran.
| |
Collapse
|
2
|
Abstract
Specificity in signal transduction is determined by the ability of cells to "encode" and subsequently "decode" different environmental signals. Akin to computer software, this "signaling code" governs context-dependent execution of cellular programs through modulation of signaling dynamics and can be corrupted by disease-causing mutations. Class IA phosphoinositide 3-kinase (PI3K) signaling is critical for normal growth and development and is dysregulated in human disorders such as benign overgrowth syndromes, cancer, primary immune deficiency, and metabolic syndrome. Despite decades of PI3K research, understanding of context-dependent regulation of the PI3K pathway and of the underlying signaling code remains rudimentary. Here, we review current knowledge on context-specific PI3K signaling and how technological advances now make it possible to move from a qualitative to quantitative understanding of this pathway. Insight into how cellular PI3K signaling is encoded or decoded may open new avenues for rational pharmacological targeting of PI3K-associated diseases. The principles of PI3K context-dependent signal encoding and decoding described here are likely applicable to most, if not all, major cell signaling pathways.
Collapse
Affiliation(s)
- Ralitsa R Madsen
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, UK.
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, UK.
| |
Collapse
|
3
|
Zheng Y, Wang K, Wu Y, Chen Y, Chen X, Hu CW, Hu F. Pinocembrin induces ER stress mediated apoptosis and suppresses autophagy in melanoma cells. Cancer Lett 2018; 431:31-42. [PMID: 29807112 DOI: 10.1016/j.canlet.2018.05.026] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/15/2018] [Accepted: 05/17/2018] [Indexed: 12/11/2022]
Abstract
Melanoma, one of the toughest tumors to treat, features high metastasis and high lethality. Pinocembrin is a natural flavanone with versatile biological and pharmacological activities. Here, we evaluated the anti-tumor effects of pinocembrin against melanoma in vitro and in vivo. In vitro, pinocembrin inhibited the proliferation of melanoma cells (B16F10 and A375) in a dose-dependent manner. It induced endoplasmic reticulum stress via IRE1α/Xbp1 pathway and triggered caspase-12/-4 mediated apoptosis in both cell lines. Furthermore, we discovered that pinocembrin suppressed autophagy through the activation of PI3K/Akt/mTOR pathway, which serves as a dual mechanism to enhance the pro-death effect of pinocembrin. In vivo, pinocembrin inhibited the growth of B16F10 by inducing apoptosis. Taken together, our results demonstrated that pinocembrin can induce ER stress mediated apoptosis and suppress autophagy in melanoma, indicating its application potential for melanoma therapy.
Collapse
Affiliation(s)
- Yufei Zheng
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Kai Wang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, 100093, China
| | - Yuqi Wu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yifan Chen
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xi Chen
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Chenyue W Hu
- Department of Bioengineering, Rice University, Houston, 77030, USA
| | - Fuliang Hu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
| |
Collapse
|
4
|
Tsai JP, Lee CH, Ying TH, Lin CL, Lin CL, Hsueh JT, Hsieh YH. Licochalcone A induces autophagy through PI3K/Akt/mTOR inactivation and autophagy suppression enhances Licochalcone A-induced apoptosis of human cervical cancer cells. Oncotarget 2016; 6:28851-66. [PMID: 26311737 PMCID: PMC4745696 DOI: 10.18632/oncotarget.4767] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/20/2015] [Indexed: 12/26/2022] Open
Abstract
The use of dietary bioactive compounds in chemoprevention can potentially reverse, suppress, or even prevent cancer progression. However, the effects of licochalcone A (LicA) on apoptosis and autophagy in cervical cancer cells have not yet been clearly elucidated. In this study, LicA treatment was found to significantly induce the apoptotic and autophagic capacities of cervical cancer cells in vitro and in vivo. MTT assay results showed dose- and time-dependent cytotoxicity in four cervical cancer cell lines treated with LicA. We found that LicA induced mitochondria-dependent apoptosis in SiHa cells, with decreasing Bcl-2 expression. LicA also induced autophagy effects were examined by identifying accumulation of Atg5, Atg7, Atg12 and microtubule-associated protein 1 light chain 3 (LC3)-II. Treatment with autophagy-specific inhibitors (3-methyladenine and bafilomycin A1) enhanced LicA-induced apoptosis. In addition, we suggested the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of mTOR pathway by LicA. Furthermore, the inhibition of PI3K/Akt by LY294002/si-Akt or of mTOR by rapamycin augmented LicA-induced apoptosis and autophagy. Finally, the in vivo mice bearing a SiHa xenograft, LicA dosed at 10 or 20 mg/kg significantly inhibited tumor growth. Our findings demonstrate the chemotherapeutic potential of LicA for treatment of human cervical cancer.
Collapse
Affiliation(s)
- Jen-Pi Tsai
- Department of Nephrology, Buddhist Dalin Tzu Chi General Hospital, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Chien-Hsing Lee
- Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan, Taiwan.,Division of Pediatric Surgery, Department of Surgery, Children's Hospital of China Medical University, Taichung, Taiwan
| | - Tsung-Ho Ying
- Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Chu-Liang Lin
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
| | - Chia-Liang Lin
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
| | - Jung-Tsung Hsueh
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
| | - Yi-Hsien Hsieh
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan.,Department of Biochemistry, School of Medicine, Chung Shan Medical University, Taichung, Taiwan.,Clinical Laboratory, Chung Shan Medical University Hospital, Taichung, Taiwan
| |
Collapse
|
5
|
Leprivier G, Rotblat B, Khan D, Jan E, Sorensen PH. Stress-mediated translational control in cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:845-60. [PMID: 25464034 DOI: 10.1016/j.bbagrm.2014.11.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/31/2014] [Accepted: 11/04/2014] [Indexed: 12/22/2022]
Abstract
Tumor cells are continually subjected to diverse stress conditions of the tumor microenvironment, including hypoxia, nutrient deprivation, and oxidative or genotoxic stress. Tumor cells must evolve adaptive mechanisms to survive these conditions to ultimately drive tumor progression. Tight control of mRNA translation is critical for this response and the adaptation of tumor cells to such stress forms. This proceeds though a translational reprogramming process which restrains overall translation activity to preserve energy and nutrients, but which also stimulates the selective synthesis of major stress adaptor proteins. Here we present the different regulatory signaling pathways which coordinate mRNA translation in the response to different stress forms, including those regulating eIF2α, mTORC1 and eEF2K, and we explain how tumor cells hijack these pathways for survival under stress. Finally, mechanisms for selective mRNA translation under stress, including the utilization of upstream open reading frames (uORFs) and internal ribosome entry sites (IRESes) are discussed in the context of cell stress. This article is part of a Special Issue entitled: Translation and Cancer.
Collapse
Affiliation(s)
- Gabriel Leprivier
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia V5Z 1L4, Canada; Department of Pathology, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Barak Rotblat
- Department of Life Science, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Debjit Khan
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia V5Z 1L4, Canada; Department of Pathology, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Eric Jan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T1Z3, Canada
| | - Poul H Sorensen
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia V5Z 1L4, Canada; Department of Pathology, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada.
| |
Collapse
|
6
|
Taguchi F, Kodera Y, Katanasaka Y, Yanagihara K, Tamura T, Koizumi F. Efficacy of RAD001 (everolimus) against advanced gastric cancer with peritoneal dissemination. Invest New Drugs 2010; 29:1198-205. [DOI: 10.1007/s10637-010-9464-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 05/20/2010] [Indexed: 12/25/2022]
|
7
|
Tanaka T, Wakamatsu T, Daijo H, Oda S, Kai S, Adachi T, Kizaka-Kondoh S, Fukuda K, Hirota K. Persisting mild hypothermia suppresses hypoxia-inducible factor-1alpha protein synthesis and hypoxia-inducible factor-1-mediated gene expression. Am J Physiol Regul Integr Comp Physiol 2009; 298:R661-71. [PMID: 20042684 DOI: 10.1152/ajpregu.00732.2009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transcription factor hypoxia-inducible factor-1 (HIF-1) plays an essential role in regulating gene expression in response to hypoxia-ischemia. Ischemia causes the tissue not only to be hypoxic but also to be hypothermic because of the hypoperfusion under certain circumstances. On the other hand, the induced hypothermia is one of the most common therapeutic modalities to extend tolerance to hypoxia. Although hypoxia elicits a variety of cellular and systemic responses at different organizational levels in the body, little is known about how hypoxia-induced responses are affected by low temperature. We examined the influence of mild hypothermic conditions (28-32 degrees C) on HIF-1 in both in vitro and in vivo settings. In vitro experiments adopting cultured cells elucidated that hypoxia-induced HIF-1 activation was resistant to 4-h exposure to the low temperature. In contrast, exposure to the low temperature as long as 24 h suppressed HIF-1 activation and the subsequent upregulation of HIF-1 target genes such as VEGF or GLUT-1. HIF-1alpha protein stability in the cell was not affected by hypothermic treatment. Furthermore, intracellular ATP content was reduced under 1% O(2) conditions but was not largely affected by hypothermic treatment. The evidence indicates that reduction of oxygen consumption is not largely involved in suppression of HIF-1. In addition, we demonstrated that HIF-1 DNA-binding activity and HIF-1-dependent gene expressions induced under 10% O(2) atmosphere in mouse brain were not influenced by treatment under 3-h hypothermic temperature but were inhibited under 5-h treatment. On the other hand, we indicated that warming ischemic legs of mice for 24 h preserved HIF-1 activity. In this report we describe for the first time that persisting low temperature significantly reduced HIF-1alpha neosynthesis under hypoxic conditions, leading to a decrease in gene expression for adaptation to hypoxia in both in vitro and in vivo settings.
Collapse
Affiliation(s)
- Tomoharu Tanaka
- Dept. of Anesthesia, Kyoto Univ. Hospital, Kyoto 606-8507, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Nakayama K. Cellular signal transduction of the hypoxia response. J Biochem 2009; 146:757-65. [PMID: 19864435 DOI: 10.1093/jb/mvp167] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cells induce the hypoxia responses to adapt to the environment when organisms are exposed to a low oxygen environment. The hypoxia response leads to the activation of multiple cellular signalling pathways involved in regulation of respiration, metabolism, cell survival and so forth. Hypoxia-Inducible-Factor (HIF) pathway plays a central role during the hypoxia response as its expression and activity are regulated in an oxygen-dependent manner and it also regulates the expression of multiple hypoxia responsive genes. The expression of HIF is regulated by proline hydroxylation, which is mediated by HIF prolyl-hydroxylase named PHD. The hydroxylated HIF-alpha subunit is degraded via the ubiquitin-proteasome pathway. The PHD activity needs to be strictly regulated to ensure the stabilization of HIF under hypoxic conditions, because PHD leads to HIF degradation. This review describes the regulatory mechanism of HIF stability and activity under normoxia and hypoxic conditions. Furthermore, the role of the HIF-independent pathways during the hypoxia response, which is as important as the HIF pathway, will also be described.
Collapse
Affiliation(s)
- Koh Nakayama
- Medical Top Track program, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
| |
Collapse
|
9
|
Ronellenfitsch MW, Brucker DP, Burger MC, Wolking S, Tritschler F, Rieger J, Wick W, Weller M, Steinbach JP. Antagonism of the mammalian target of rapamycin selectively mediates metabolic effects of epidermal growth factor receptor inhibition and protects human malignant glioma cells from hypoxia-induced cell death. ACTA ACUST UNITED AC 2009; 132:1509-22. [PMID: 19416948 DOI: 10.1093/brain/awp093] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Although inhibition of the epidermal growth factor receptor is a plausible therapy for malignant gliomas that, in vitro, enhances apoptosis, the results of clinical trials have been disappointing. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that integrates starvation signals and generates adaptive responses that aim at the maintenance of energy homeostasis. Antagonism of mTOR has been suggested as a strategy to augment the efficacy of epidermal growth factor receptor inhibition by interfering with deregulated signalling cascades downstream of Akt. Here we compared effects of antagonism of mTOR utilizing rapamycin or a small hairpin RNA-mediated gene silencing to those of epidermal growth factor receptor inhibition or combined inhibition of epidermal growth factor receptor and mTOR in human malignant glioma cells. In contrast to epidermal growth factor receptor inhibition, mTOR antagonism neither induced cell death nor enhanced apoptosis induced by CD95 ligand or chemotherapeutic drugs. However, mTOR inhibition mimicked the hypoxia-protective effects of epidermal growth factor receptor inhibition by maintaining adenosine triphosphate levels. These in vitro experiments thus challenge the current view of mTOR as a downstream target of Akt that mediates antiapoptotic stimuli. Under the conditions of the tumour microenvironment, metabolic effects of inhibition of epidermal growth factor receptor, Akt and mTOR may adversely affect outcome by protecting the hypoxic tumour cell fraction.
Collapse
Affiliation(s)
- Michael W Ronellenfitsch
- Dr. Senckenberg Institute of Neurooncology, Centre of Neurology and Neurosurgery, Goethe-University Hospital, Schleusenweg 2-16, Frankfurt am Main, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Choi SE, Lee SM, Lee YJ, Li LJ, Lee SJ, Lee JH, Kim Y, Jun HS, Lee KW, Kang Y. Protective role of autophagy in palmitate-induced INS-1 beta-cell death. Endocrinology 2009; 150:126-34. [PMID: 18772242 DOI: 10.1210/en.2008-0483] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Autophagy, a vacuolar degradative pathway, constitutes a stress adaptation that avoids cell death or elicits the alternative cell-death pathway. This study was undertaken to determine whether autophagy is activated in palmitate (PA)-treated beta-cells and, if activated, what the role of autophagy is in the PA-induced beta-cell death. The enhanced formation of autophagosomes and autolysosomes was observed by exposure of INS-1 beta-cells to 400 microm PA in the presence of 25 mm glucose for 12 h. The formation of green fluorescent protein-LC3-labeled structures (green fluorescent protein-LC3 dots), with the conversion from LC3-I to LC3-II, was also distinct in the PA-treated cells. The phospho-mammalian target of rapamycin level, a typical signal pathway that inhibits activation of autophagy, was gradually decreased by PA treatment. Blockage of the mammalian target of rapamycin signaling pathway by treatment with rapamycin augmented the formation of autophagosomes but reduced PA-induced INS-1 cell death. In contrast, reduction of autophagosome formation by knocking down the ATG5, inhibition of fusion between autophagosome and lysosome by treatment with bafilomycin A1, or inhibition of proteolytic degradation by treatment with E64d/pepstatin A, significantly augmented PA-induced INS-1 cell death. These findings showed that the autophagy system could be activated in PA-treated INS-1 beta-cells, and suggested that the induction of autophagy might play an adaptive and protective role in PA-induced cell death.
Collapse
Affiliation(s)
- Sung-E Choi
- Institute for Medical Science, Ajou University School of Medicine, Wonchon-dong san5, Yongtong-gu, Suwon, Gyeonggi-do 442-749, Republic of Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Isohashi F, Endo H, Mukai M, Inoue T, Inoue M. Insulin-like growth factor stimulation increases radiosensitivity of a pancreatic cancer cell line through endoplasmic reticulum stress under hypoxic conditions. Cancer Sci 2008; 99:2395-401. [PMID: 19018773 PMCID: PMC11159351 DOI: 10.1111/j.1349-7006.2008.00970.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/04/2008] [Accepted: 08/13/2008] [Indexed: 01/22/2023] Open
Abstract
Tumor hypoxia is an obstacle to radiotherapy. Radiosensitivity under hypoxic conditions is determined by molecular oxygen levels, as well as by various biological cellular responses. The insulin-like growth factor (IGF) signaling pathway is a widely recognized survival signal that confers radioresistance. However, under hypoxic conditions the role of IGF signaling in radiosensitivity is still poorly understood. Here, we demonstrate that IGF-II stimulation decreases clonogenic survival under hypoxic conditions in the pancreatic cancer cell lines AsPC-1 and Panc-1, and in the human breast cancer cell line MCF-7. IGF treatment under hypoxic conditions suppressed increased radiation sensitivity in these cell lines by pharmacologically inhibiting the phosphoinositide 3-kinase-mammalian target of rapamycin pathway, a major IGF signal-transduction pathway. Meanwhile, IGF-II induced the endoplasmic reticulum stress response under hypoxia, including increased protein levels of CHOP and ATF4, mRNA levels of CHOP, GADD34, and BiP, as well as splicing levels of XBP-1. The response was suppressed by inhibiting phosphoinositide 3-kinase and mammalian target of rapamycin activity. Overexpression of CHOP in AsPC-1 cells increased radiation sensitivity by IGF-II simulation under hypoxic conditions, whereas suppression of CHOP expression levels with small hairpin RNA or a dominant negative form of a proline-rich extensin-like receptor protein kinase in hypoxia decreased IGF-induced radiosensitivity. IGF-induced endoplasmic reticulum stress contributed to radiosensitization independent of cell cycle status. Taken together, IGF stimulation increased radiosensitivity through the endoplasmic reticulum stress response under hypoxic conditions.
Collapse
Affiliation(s)
- Fumiaki Isohashi
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka 537-8511, Japan
| | | | | | | | | |
Collapse
|
12
|
Wangpaichitr M, Savaraj N, Maher J, Kurtoglu M, Lampidis TJ. Intrinsically lower AKT, mammalian target of rapamycin, and hypoxia-inducible factor activity correlates with increased sensitivity to 2-deoxy-D-glucose under hypoxia in lung cancer cell lines. Mol Cancer Ther 2008; 7:1506-13. [PMID: 18566221 DOI: 10.1158/1535-7163.mct-07-2334] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Down-regulation by small interfering RNA or absence of hypoxia-inducible factor (HIF-1alpha) has been shown to lead to increased sensitivity to glycolytic inhibitors in hypoxic tumor cells. In surveying a number of tumor types for differences in intrinsic levels of HIF under hypoxia, we find that the reduction of the upstream pathways of HIF, AKT, and mammalian target of rapamycin (mTOR) correlates with increased toxic effects of 2-deoxy-D-glucose (2-DG) in lung cancer cell lines when treated under hypoxia. Because HIF-1alpha translation is regulated by mTOR, we examined the effects of blocking mTOR under hypoxia with an analogue of rapamycin (CCI-779) in those cell lines that showed increased mTOR and AKT activity and found that HIF-1alpha down-regulation coincided with increased 2-DG killing. CCI-779, however, was ineffective in increasing 2-DG toxicity in cell lines that did not express HIF. These results support the hypothesis that although mTOR inhibition leads to the blockage of numerous downstream targets, CCI-779 increases the toxicity of 2-DG in hypoxic cells through down-regulation of HIF-1alpha. Overall, our findings show that CCI-779 hypersensitizes hypoxic tumor cells to 2-DG and suggests that the intrinsic expression of AKT, mTOR, and HIF in lung cancer, as well as other tumor types, may be important in dictating the decision on how best to use 2-DG alone or in combination with CCI-799 to kill hypoxic tumor cells clinically.
Collapse
Affiliation(s)
- Medhi Wangpaichitr
- Department of Molecular Cell Biology and Anatomy, Miller School of Medicine, University of Miami, Miami, FL 33101, USA
| | | | | | | | | |
Collapse
|
13
|
Yoshiba S, Ito D, Nagumo T, Shirota T, Hatori M, Shintani S. Hypoxia induces resistance to 5-fluorouracil in oral cancer cells via G(1) phase cell cycle arrest. Oral Oncol 2008; 45:109-15. [PMID: 18710819 DOI: 10.1016/j.oraloncology.2008.04.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 04/03/2008] [Accepted: 04/03/2008] [Indexed: 01/15/2023]
Abstract
Malignant tumors are exposed to various levels of hypoxic condition in vivo. It has been known that tumor cells under hypoxia are resistant to chemotherapies. To clarify the mechanism of the hypoxia-induced chemoresistance, we evaluated the effects of hypoxia on the resistance of oral squamous cell carcinoma (OSCC) cell lines to 5-fluorouracil (5-FU). OSCC cells were divided to two groups by the proliferation activity under hypoxic condition; hypoxia-resistant (HR) and hypoxia-sensitive (HS) cells. Growth of HS cells were inhibited by hypoxia and introduced to G(1) arrest in cell cycle. 5-FU effect on HS cell viability was markedly reduced in hypoxic condition without an induction of chemoresistant related protein, P-glycoprotein. However, proliferation, cell cycle, and 5-FU sensitivity of HR cells were not affected by hypoxia. Hypoxia-inducible factor (HIF)-1alpha was induced by hypoxia in all OSCC cell lines, but diminished in HS cells within 48h. Expression of p21 and p27 was strongly augmented and CyclinD expression was reduced by hypoxia in HS cells. However, the expression of these proteins was constitutive in HR cells during 48h hypoxic culture. Phosphorylation of mammalian target of rapamycin (mTOR) was reduced by hypoxia in HS cells. From these findings, we concluded that HS OSCC cells acquire 5-FU resistance under hypoxia by G(1)/S transition through an upregulation of cell cycle inhibitors.
Collapse
Affiliation(s)
- Sayaka Yoshiba
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Kitasenzoku 2-1-1, Ohta-ku, Tokyo 145-8515, Japan.
| | | | | | | | | | | |
Collapse
|
14
|
Koga T, Endo H, Miyamoto Y, Mukai M, Akira S, Inoue M. IGFBPs contribute to survival of pancreatic cancer cells under severely hypoxic conditions. Cancer Lett 2008; 268:82-8. [PMID: 18467023 DOI: 10.1016/j.canlet.2008.03.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 02/15/2008] [Accepted: 03/25/2008] [Indexed: 12/31/2022]
Abstract
Protein synthesis in general is suppressed under hypoxic conditions in both cancer cells and normal cells. In human pancreatic cancer AsPC-1 cells, which are resistant to low oxygen tension, protein synthesis at day 4 under hypoxia (1% O(2)) was about 20% of that under normoxia. Secretion of some proteins actually increased in spite of a general reduction in protein synthesis; two of these proteins were insulin-like growth factor binding protein-1 (IGFBP-1) and IGFBP-3. Hypoxia also induced transcription of multiple IGFBPs. The IGFBPs contributed to reduced IGF signaling and to the survival of cancer cells under conditions of low oxygen tension.
Collapse
Affiliation(s)
- Takumi Koga
- Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka 537-8511, Japan
| | | | | | | | | | | |
Collapse
|
15
|
Borger DR, Gavrilescu LC, Bucur MC, Ivan M, Decaprio JA. AMP-activated protein kinase is essential for survival in chronic hypoxia. Biochem Biophys Res Commun 2008; 370:230-4. [PMID: 18359290 DOI: 10.1016/j.bbrc.2008.03.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 03/13/2008] [Indexed: 12/12/2022]
Abstract
This study was undertaken to interrogate cancer cell survival during long-term hypoxic stress. Two systems with relevance to carcinogenesis were employed: Fully transformed BJ cells and a renal carcinoma cell line (786-0). The dynamic of AMPK activity was consistent with a prosurvival role during chronic hypoxia. This was further supported by the effects of AMPK agonists and antagonists (AICAR and compound C). Expression of a dominant-negative AMPK alpha resulted in a decreased ATP level and significantly compromised survival in hypoxia. Dose-dependent prosurvival effects of rapamycin were consistent with mTOR inhibition being a critical downstream mediator of AMPK in persistent low oxygen.
Collapse
Affiliation(s)
- Darrell R Borger
- Dana-Farber Cancer Institute, Department of Medical Oncology, Harvard Medical School, Mayer Building 440, 44 Binney Street, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
16
|
Endo H, Murata K, Mukai M, Ishikawa O, Inoue M. Activation of insulin-like growth factor signaling induces apoptotic cell death under prolonged hypoxia by enhancing endoplasmic reticulum stress response. Cancer Res 2007; 67:8095-103. [PMID: 17804721 DOI: 10.1158/0008-5472.can-06-3389] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Malignant cells in solid tumors survive under prolonged hypoxia and can be a source of resistance to current cancer therapies. Mammalian target of rapamycin (mTOR), one of the downstream molecules of the insulin-like growth factor (IGF) pathway, is a key regulator of translation, integrating multiple environmental and nutritional cues. The activity of mTOR is known to be suppressed under hypoxic conditions in cancer cells, whereas the contribution of this suppression to cell survival has not yet been clarified. We show that stimulating IGF signaling provoked caspase-dependent apoptosis under low oxygen tension in two cancer cell lines, COLO 320 and AsPC-1. In concurrence with increased levels of BAD phosphorylation, cell death was not accompanied by cytochrome c release from mitochondria. The cells were rescued from apoptosis when phosphatidylinositol 3-kinase (PI3K) or mTOR activity was inhibited, suggesting that these signals are critical in the observed cell death. IGFs and insulin enhanced the endoplasmic reticulum (ER) stress response as monitored by induction of the CCAAT/enhancer binding protein homologous protein (CHOP) proteins and the X box protein-1 splicing under hypoxic conditions, and this response was suppressed by inhibiting PI3K and mTOR activity. IGF-induced cell death under hypoxic conditions was prevented by treatment with cycloheximide, suggesting that de novo protein synthesis is required. Indeed, suppression of CHOP protein levels with small hairpin RNA reduced cell death. Taken together, the data suggest that stimulating IGF signaling under hypoxic conditions provokes apoptosis by enhancing the ER stress response.
Collapse
Affiliation(s)
- Hiroko Endo
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Suita Municipal Hospital, Osaka, Japan
| | | | | | | | | |
Collapse
|
17
|
Abstract
Proteins regulating the mammalian target of rapamycin (mTOR), as well as some of the targets of the mTOR kinase, are overexpressed or mutated in cancer. Rapamycin, the naturally occurring inhibitor of mTOR, along with a number of recently developed rapamycin analogs (rapalogs) consisting of synthetically derived compounds containing minor chemical modifications to the parent structure, inhibit the growth of cell lines derived from multiple tumor types in vitro, and tumor models in vivo. Results from clinical trials indicate that the rapalogs may be useful for the treatment of subsets of certain types of cancer. The sporadic responses from the initial clinical trials, based on the hypothesis of general translation inhibition of cancer cells are now beginning to be understood owing to a more complete understanding of the dynamics of mTOR regulation and the function of mTOR in the tumor microenvironment. This review will summarize the preclinical and clinical data and recent discoveries of the function of mTOR in cancer and growth regulation.
Collapse
Affiliation(s)
- J B Easton
- Department of Molecular Pharmacology, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | |
Collapse
|
18
|
Kusama T, Mukai M, Endo H, Ishikawa O, Tatsuta M, Nakamura H, Inoue M. Inactivation of Rho GTPases by p190 RhoGAP reduces human pancreatic cancer cell invasion and metastasis. Cancer Sci 2006; 97:848-53. [PMID: 16776779 PMCID: PMC11158153 DOI: 10.1111/j.1349-7006.2006.00242.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A number of small GTPases are involved in cancer cell proliferation, migration and invasion, acting as molecular switches that cycle between GTP- and GDP-bound states. GTPase-activating proteins (GAPs) have been established as a major class of negative regulators of Rho GTPase signaling. To investigate the biological function of p190 RhoGAP toward RhoA in cancer cell invasion and metastasis, we generated a chimera made of the RhoGAP domain of p190 and the C-terminus of RhoA (p190-RhoA chimera), and transfected it into human pancreatic cancer cells, AsPC-1. Epidermal growth factor (EGF)-induced activation of RhoA, as well as RhoB and RhoC, to a lesser extent, was significantly inhibited in p190-RhoA chimera-transfected AsPC-1 cells compared with that of control cells (mock-infected), when assessed by pull-down assay for GTP-bound RhoA, RhoB, and RhoC, respectively. EGF-induced invasion of p190-RhoA chimera transfectants was significantly inhibited compared with that of mock-infected cells in a modified Boyden chamber assay. Furthermore, the mice injected intrasplenically with AsPC-1 cells that overexpressed the p190-RhoA chimera had a marked reduction in the number and size of metastatic nodules in the liver. These data suggest that the inhibitory action of p190 RhoGAP toward RhoA offers a novel approach to the treatment of invasion and metastasis of cancer cells.
Collapse
Affiliation(s)
- Toshiyuki Kusama
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan
| | | | | | | | | | | | | |
Collapse
|
19
|
Shojaiefard M, Christie DL, Lang F. Stimulation of the creatine transporter SLC6A8 by the protein kinase mTOR. Biochem Biophys Res Commun 2006; 341:945-9. [PMID: 16466692 DOI: 10.1016/j.bbrc.2006.01.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 01/17/2006] [Indexed: 12/20/2022]
Abstract
Cellular accumulation of creatine is accomplished by the Na(+), Cl(-), and creatine transporter CreaT (SLC6A8). The mammalian target of rapamycin (mTOR) is a kinase stimulating cellular nutrient uptake. The present experiments explored whether SLC6A8 is regulated by mTOR. In Xenopus oocytes expressing SLC6A8 but not in water injected oocytes, creatine-induced a current which was significantly enhanced by coexpression of mTOR. Kinetic analysis revealed that mTOR enhanced maximal current without significantly altering affinity. Preincubation of the oocytes for 32 h with rapamycin (50 nM) decreased the creatine-induced current and abrogated its stimulation by mTOR. The effect of mTOR on CreaT was blunted by additional coexpression of the inactive mutant of the serum and glucocorticoid-inducible kinase (K119N)SGK1 and mimicked by coexpression of wild type SGK1. In conclusion, mTOR stimulates the creatine transporter SLC6A8 through mechanisms at least partially shared by the serum and glucocorticoid-inducible kinase SGK1.
Collapse
|