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Wang J, Liang Q, Zhao Q, Tang Q, Ahmed AF, Zhang Y, Kang W. The effect of microbial composition and proteomic on improvement of functional constipation by Chrysanthemum morifolium polysaccharide. Food Chem Toxicol 2021; 153:112305. [PMID: 34033886 DOI: 10.1016/j.fct.2021.112305] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/16/2021] [Accepted: 05/19/2021] [Indexed: 02/07/2023]
Abstract
In this paper, SD rat constipation model was established with loperamide hydrochloride to study the effect of Chrysanthemum morifolium polysaccharide on the improvement of functional constipation, and the mechanism of improving constipation was investigated with the proteomics and intestinal flora. The results showed that the HD group of C. morifolium polysaccharide could significantly increase the levels of water content of stool pellets, small intestine propulsion rate, gastrin (MTL), gastrin (GAS) and substance P (SP), decrease the level of growth inhibitor (SS) and improved gastrointestinal motility in rats. Gut microbial studies showed that C. morifolium polysaccharide could significantly increase species abundance and flora diversity and improve flora structure. The relative abundance of Lactobacillus and Romboutsia increased, while the relative abundance of Lachnospiraceae_NK4A136_group and Roseburia decreased compared with the MC group. Proteomics studies suggested that C. morifolium polysaccharides could reduce intestinal lesions, enhance intestinal homeostasis, increase amino acid uptake, promote intestinal motility and relieve constipation by regulating the expression of RAS, FABP1 and SLC1A5 proteins.
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Affiliation(s)
- Jinmei Wang
- National R & D Center for Edible Fungus Processing Technology, Henan University, Kaifeng, 475004, China; Functional Food Engineering Technology Research Center, Kaifeng, 475004, China
| | - Qiongxin Liang
- National R & D Center for Edible Fungus Processing Technology, Henan University, Kaifeng, 475004, China; Functional Food Engineering Technology Research Center, Kaifeng, 475004, China
| | - Qingchun Zhao
- National R & D Center for Edible Fungus Processing Technology, Henan University, Kaifeng, 475004, China
| | - Qi Tang
- National R & D Center for Edible Fungus Processing Technology, Henan University, Kaifeng, 475004, China
| | - Adel F Ahmed
- Medicinal and Aromatic Plants Researches Department, Horticulture Research Institute, Agricultural Research Center, Giza, 71625, Egypt.
| | - Yan Zhang
- Hebei Food Inspection and Research Institute, Hebei Food Safety Key Laboratory, Shijiazhuang, 050227, China; Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Shijiazhuang, 050227, China.
| | - Wenyi Kang
- National R & D Center for Edible Fungus Processing Technology, Henan University, Kaifeng, 475004, China; Functional Food Engineering Technology Research Center, Kaifeng, 475004, China.
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2
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Fritsch SD, Weichhart T. Metabolic and immunologic control of intestinal cell function by mTOR. Int Immunol 2020; 32:455-465. [PMID: 32140726 DOI: 10.1093/intimm/dxaa015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023] Open
Abstract
The intestinal epithelium is one of the most quickly dividing tissues in our body, combining the absorptive advantages of a single layer with the protection of a constantly renewing barrier. It is continuously exposed to nutrients and commensal bacteria as well as microbial and host-derived metabolites, but also to hazards such as pathogenic bacteria and toxins. These environmental cues are sensed by the mucosa and a vast repertory of immune cells, especially macrophages. A disruption of intestinal homeostasis in terms of barrier interruption can lead to inflammatory bowel diseases and colorectal cancer, and macrophages have an important role in restoring epithelial function following injury. The mammalian/mechanistic target of rapamycin (mTOR) signalling pathway senses environmental cues and integrates metabolic responses. It has emerged as an important regulator of intestinal functions in homeostasis and disease. In this review, we are going to discuss intestinal mTOR signalling and metabolic regulation in different intestinal cell populations with a special focus on immune cells and their actions on intestinal function.
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Affiliation(s)
- Stephanie D Fritsch
- Center of Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, Währinger Straße, Vienna, Austria
| | - Thomas Weichhart
- Center of Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, Währinger Straße, Vienna, Austria
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Paulino DSM, Mendes MCS, Camargo JA, Brambilla SR, Wood Dos Santos T, Ribeiro ML, Carvalheira JBC. Diacerein treatment prevents colitis-associated cancer in mice. World J Clin Oncol 2020; 11:732-746. [PMID: 33033695 PMCID: PMC7522546 DOI: 10.5306/wjco.v11.i9.732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/06/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Inflammation is a well-established enabling factor for cancer development and provides a framework for the high prevalence of colon cancer in inflammatory bowel disease. In accordance, chronic inflammation has recently been implicated in the development of cancer stem cells (CSCs). However, the mechanism whereby anti-inflammatory drugs act in the prevention of colitis-associated cancer (CAC) is only partially understood. AIM To evaluate the role of diacerein (DAR), an anti-inflammatory drug that mainly acts through the inhibition of interleukin (IL)-1β expression in the development of CSCs and CAC. METHODS The effects of DAR on colon inflammation in mice with CAC were evaluated by inflammatory index, reverse real-time transcription polymerase chain reaction and western blot. Cytokine levels were measured by enzyme-linked immunosorbent assay. Cells assays evaluated the effects of DAR on CSCs. Immunohistochemistry and apoptosis assays were also used to evaluate the effects of DAR on tumorigenesis associated with inflammation. RESULTS DAR treatment reduced colon inflammation as well as the number and size of tumors in azoxymethane plus dextran sulphate sodium-treated animals. Accordingly, DAR treatment was associated with reduced intracellular signals of inflammation (inhibitor of nuclear factor kappa B kinase and c-Jun N-terminal kinase phosphorylation) in the colon. In addition, DAR treatment was associated with a decrease in colon CSC formation, suggesting that besides reducing colonic inflammation, DAR has a direct effect on the inhibition of colon carcinogenesis. CONCLUSION Together, these data indicate that DAR-mediated IL-1β suppression attenuates inflammation-induced colon cancer and CSC formation, highlighting DAR as a potential candidate for the chemoprevention of CAC.
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Affiliation(s)
- Daiane S M Paulino
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Sao Paulo 13083-970, Brazil
| | - Maria Carolina S Mendes
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Sao Paulo 13083-970, Brazil
| | - Juliana A Camargo
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Sao Paulo 13083-970, Brazil
| | - Sandra R Brambilla
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Sao Paulo 13083-970, Brazil
| | - Tanila Wood Dos Santos
- Department of Clinical Pharmacology and Gastroenterology, Sao Francisco University, Sao Paulo 12916-900, Brazil
| | - Marcelo L Ribeiro
- Department of Clinical Pharmacology and Gastroenterology, Sao Francisco University, Sao Paulo 12916-900, Brazil
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McManus S, Chababi W, Arsenault D, Dubois CM, Saucier C. Dissecting Oncogenic RTK Pathways in Colorectal Cancer Initiation and Progression. Methods Mol Biol 2018; 1765:27-42. [PMID: 29589299 DOI: 10.1007/978-1-4939-7765-9_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Colorectal cancer (CRC) is a progressive disorder associated with an accumulation of multiple heterogeneous genetic alterations in intestinal epithelial cells (IEC). However, when these cells undergo neoplastic transformation and become cancerous and metastatic, they invariably acquire hallmarks conferring them the ability to hyperproliferate, escape growth-inhibitory and death-inducing cues, and promote angiogenesis as well as epithelial-to-mesenchymal transformation (EMT), fostering their invasive dissemination from primary tumor into distant tissues. Compelling clinical and experimental evidence suggest that aberrant engagement of cell surface growth factor receptor tyrosine kinase (RTK) signaling, like that of the hepatocyte growth factor (HGF)/MET receptor, underlies CRC metastatic progression by promoting these cancer hallmarks. To date, though, the use of RTK-targeting agents has been viewed as a promising approach for the treatment of metastatic CRC, clinical success has been modest.Our vision is that the prospect of designing RTK-based, improved and innovative CRC therapies and prognostic markers likely rests on a comprehensive understanding of the biological processes and underlying regulatory molecular mechanisms by which deregulation of RTK signaling governs IEC's neoplastic transformation and their transition from noninvasive to metastatic and malignant cells. Herein, we describe our scheme for defining the full scope of oncogenic MET-driven cancer biological processes, in cellulo and in vivo, as well as the individual contribution of MET-binding effectors in a nontransformed IEC model, the IEC-6 cell line.
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Affiliation(s)
- Stephen McManus
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Walid Chababi
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Dominique Arsenault
- Department of Pediatrics, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
- Department of Immunology Division, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Claire M Dubois
- Department of Pediatrics, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
- Department of Immunology Division, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Caroline Saucier
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Science, Université de Sherbrooke, Sherbrooke, QC, Canada.
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Ketogenesis contributes to intestinal cell differentiation. Cell Death Differ 2016; 24:458-468. [PMID: 27935584 DOI: 10.1038/cdd.2016.142] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/18/2016] [Accepted: 11/04/2016] [Indexed: 01/01/2023] Open
Abstract
The intestinal epithelium undergoes a continual process of proliferation, differentiation and apoptosis. Previously, we have shown that the PI3K/Akt/mTOR pathway has a critical role in intestinal homeostasis. However, the downstream targets mediating the effects of mTOR in intestinal cells are not known. Here, we show that the ketone body β-hydroxybutyrate (βHB), an endogenous inhibitor of histone deacetylases (HDACs) induces intestinal cell differentiation as noted by the increased expression of differentiation markers (Mucin2 (MUC2), lysozyme, IAP, sucrase-isomaltase, KRT20, villin, Caudal-related homeobox transcription factor 2 (CDX2) and p21Waf1). Conversely, knockdown of the ketogenic mitochondrial enzyme hydroxymethylglutaryl CoA synthase 2 (HMGCS2) attenuated spontaneous differentiation in the human colon cancer cell line Caco-2. Overexpression of HMGCS2, which we found is localized specifically in the more differentiated portions of the intestinal mucosa, increased the expression of CDX2, thus further suggesting the contributory role of HMGCS2 in intestinal differentiation. In addition, mice fed a ketogenic diet demonstrated increased differentiation of intestinal cells as noted by an increase in the enterocyte, goblet and Paneth cell lineages. Moreover, we showed that either knockdown of mTOR or inhibition of mTORC1 with rapamycin increases the expression of HMGCS2 in intestinal cells in vitro and in vivo, suggesting a possible cross-talk between mTOR and HMGCS2/βHB signaling in intestinal cells. In contrast, treatment of intestinal cells with βHB or feeding mice with a ketogenic diet inhibits mTOR signaling in intestinal cells. Together, we provide evidence showing that HMGCS2/βHB contributes to intestinal cell differentiation. Our results suggest that mTOR acts cooperatively with HMGCS2/βHB to maintain intestinal homeostasis.
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Lien GS, Lin CH, Yang YL, Wu MS, Chen BC. Ghrelin induces colon cancer cell proliferation through the GHS-R, Ras, PI3K, Akt, and mTOR signaling pathways. Eur J Pharmacol 2016; 776:124-31. [PMID: 26879868 DOI: 10.1016/j.ejphar.2016.02.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/11/2016] [Accepted: 02/11/2016] [Indexed: 12/16/2022]
Abstract
Colon cancer is the third most common malignancy worldwide. Recently, some interesting associations between ghrelin and cancer were reported, and it may participate in colon cancer development. In the present report, we explored the role of the growth hormone secretagogue receptor (GHS-R), Ras, phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR) pathways in the ghrelin-induced proliferation of human colon cancer cells. Ghrelin-caused HT-29 proliferation was reduced by [D-Lys3]-GHRP-6 (a GHS-R inhibitor). We also found that a dominant negative mutant of Ras (Ras DN), a PI3K inhibitor (LY 294002), an Akt DN, and an mTOR inhibitor (rapamycin) attenuated ghrelin-caused colon cancer cell proliferation. We found that ghrelin induced time-dependent increases in Ras activity. Moreover, ghrelin-mediated Akt Ser473 phosphorylation was attenuated by a Ras DN and LY 294002. Furthermore, a Ras DN, LY 294002, and an Akt DN all inhibited ghrelin-caused mTOR Ser2448 phosphorylation. These results indicate that the Ras/PI3K/Akt/mTOR cascade plays a critical role in ghrelin-induced colon cancer cell proliferation.
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Affiliation(s)
- Gi-Shih Lien
- Division of Gastroenterology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 110, Taiwan
| | - Chien-Huang Lin
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - You-Lan Yang
- School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Ming-Shun Wu
- Division of Gastroenterology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 110, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Bing-Chang Chen
- School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
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Guan Y, Zhang L, Li X, Zhang X, Liu S, Gao N, Li L, Gao G, Wei G, Chen Z, Zheng Y, Ma X, Siwko S, Chen JL, Liu M, Li D. Repression of Mammalian Target of Rapamycin Complex 1 Inhibits Intestinal Regeneration in Acute Inflammatory Bowel Disease Models. THE JOURNAL OF IMMUNOLOGY 2015; 195:339-46. [PMID: 26026060 DOI: 10.4049/jimmunol.1303356] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/04/2015] [Indexed: 12/21/2022]
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway integrates environmental cues to regulate cell growth and survival through various mechanisms. However, how mTORC1 responds to acute inflammatory signals to regulate bowel regeneration is still obscure. In this study, we investigated the role of mTORC1 in acute inflammatory bowel disease. Inhibition of mTORC1 activity by rapamycin treatment or haploinsufficiency of Rheb through genetic modification in mice impaired intestinal cell proliferation and induced cell apoptosis, leading to high mortality in dextran sodium sulfate- and 2,4,6-trinitrobenzene sulfonic acid-induced colitis models. Through bone marrow transplantation, we found that mTORC1 in nonhematopoietic cells played a major role in protecting mice from colitis. Reactivation of mTORC1 activity by amino acids had a positive therapeutic effect in mTORC1-deficient Rheb(+/-) mice. Mechanistically, mTORC1 mediated IL-6-induced Stat3 activation in intestinal epithelial cells to stimulate the expression of downstream targets essential for cell proliferation and tissue regeneration. Therefore, mTORC1 signaling critically protects against inflammatory bowel disease through modulation of inflammation-induced Stat3 activity. As mTORC1 is an important therapeutic target for multiple diseases, our findings will have important implications for the clinical usage of mTORC1 inhibitors in patients with acute inflammatory bowel disease.
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Affiliation(s)
- Yuting Guan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Long Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xia Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xinyan Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Shijie Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Na Gao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Liang Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Ganglong Gao
- Fengxian Hospital, Southern Medical University, Shanghai 201499, China; and
| | - Gaigai Wei
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhaohua Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yansen Zheng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xueyun Ma
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Stefan Siwko
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030
| | - Jin-Lian Chen
- Fengxian Hospital, Southern Medical University, Shanghai 201499, China; and
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China;
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Zhou Y, Rychahou P, Wang Q, Weiss HL, Evers BM. TSC2/mTORC1 signaling controls Paneth and goblet cell differentiation in the intestinal epithelium. Cell Death Dis 2015; 6:e1631. [PMID: 25654764 PMCID: PMC4669793 DOI: 10.1038/cddis.2014.588] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 12/18/2022]
Abstract
The intestinal mucosa undergoes a continual process of proliferation, differentiation and apoptosis, which is regulated by multiple signaling pathways. Notch signaling is critical for the control of intestinal stem cell maintenance and differentiation. However, the precise mechanisms involved in the regulation of differentiation are not fully understood. Previously, we have shown that tuberous sclerosis 2 (TSC2) positively regulates the expression of the goblet cell differentiation marker, MUC2, in intestinal cells. Using transgenic mice constitutively expressing a dominant negative TSC2 allele, we observed that TSC2 inactivation increased mTORC1 and Notch activities, and altered differentiation throughout the intestinal epithelium, with a marked decrease in the goblet and Paneth cell lineages. Conversely, treatment of mice with either Notch inhibitor dibenzazepine (DBZ) or mTORC1 inhibitor rapamycin significantly attenuated the reduction of goblet and Paneth cells. Accordingly, knockdown of TSC2 activated, whereas knockdown of mTOR or treatment with rapamycin decreased, the activity of Notch signaling in the intestinal cell line LS174T. Importantly, our findings demonstrate that TSC2/mTORC1 signaling contributes to the maintenance of intestinal epithelium homeostasis by regulating Notch activity.
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Affiliation(s)
- Y Zhou
- Markey Cancer Center, The University of Kentucky, Lexington, KY, USA
| | - P Rychahou
- 1] Markey Cancer Center, The University of Kentucky, Lexington, KY, USA [2] Department of Surgery, The University of Kentucky, Lexington, KY, USA
| | - Q Wang
- 1] Markey Cancer Center, The University of Kentucky, Lexington, KY, USA [2] Department of Surgery, The University of Kentucky, Lexington, KY, USA
| | - H L Weiss
- Markey Cancer Center, The University of Kentucky, Lexington, KY, USA
| | - B M Evers
- 1] Markey Cancer Center, The University of Kentucky, Lexington, KY, USA [2] Department of Surgery, The University of Kentucky, Lexington, KY, USA
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Abstract
The mammalian target of rapamycin (mTOR) has emerged as a potential target for drug development, particularly due to the fact that it plays such a crucial role in cancer biology. In addition, next-generation mTOR inhibitors have become available, marking an exciting new phase in mTOR-based therapy. However, the verdict on their therapeutic efectiveness remains unclear. Here we review phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR signaling as one of the primary mechanisms for sustaining tumor outgrowth and metastasis, recent advances in the development of mTOR inhibitors, and current studies addressing mTOR activation/inhibition in colorectal cancer (CRC). We will also discuss our recent comparative study of diferent mTOR inhibitors in a population of colon cancer stem cells (CSCs), and current major challenges for achieving individualized drug therapy using kinase inhibitors.
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10
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Francipane MG, Lagasse E. Selective targeting of human colon cancer stem-like cells by the mTOR inhibitor Torin-1. Oncotarget 2014; 4:1948-62. [PMID: 24185040 PMCID: PMC3875761 DOI: 10.18632/oncotarget.1310] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Metastatic colorectal cancer (CRC) is incurable for most patients. Since mammalian target of rapamycin (mTOR) has been suggested as a crucial modulator of tumor biology, we aimed at evaluating the effectiveness of mTOR targeting for CRC therapy. To this purpose, we analyzed mTOR expression and the effect of mTOR inhibition in cancer stem-like cells isolated from three human metastatic CRCs (CoCSCs). CoCSCs exhibited a strong mTOR complex 2 (mTORC2) expression, and a rare expression of mTOR complex 1 (mTORC1). This latter correlated with differentiation, being expressed in CoCSC-derived xenografts. We indicate Serum/glucocorticoid-regulated kinase 1 (SGK1) as the possible main mTORC2 effector in CoCSCs, as highlighted by the negative effect on cancer properties following its knockdown. mTOR inhibitors affected CoCSCs differently, resulting in proliferation, autophagy as well as apoptosis induction. The apoptosis-inducing mTOR inhibitor Torin-1 hindered growth, motility, invasion, and survival of CoCSCs in vitro, and suppressed tumor growth in vivo with a concomitant reduction in vessel formation. Torin-1 also affected the expression of markers for cell proliferation, angio-/lympho-genesis, and stemness in vivo, including Ki67, DLL1, DLL4, Notch, Lgr5, and CD44. Importantly, Torin-1 did not affect the survival of normal colon stem cells in vivo, suggesting its selectivity towards cancer cells. Thus, we propose Torin-1 as a powerful drug candidate for metastatic CRC therapy.
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Affiliation(s)
- Maria Giovanna Francipane
- McGowan Institute for Regenerative Medicine, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Zou Z, Zhang J, Zhang H, Liu H, Li Z, Cheng D, Chen J, Liu L, Ni M, Zhang Y, Yao J, Zhou J, Fu J, Liang Y. 3-Methyladenine can depress drug efflux transporters via blocking the PI3K-AKT-mTOR pathway thus sensitizing MDR cancer to chemotherapy. J Drug Target 2014; 22:839-48. [PMID: 25019701 DOI: 10.3109/1061186x.2014.936870] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Multi-drug resistance (MDR) cancer is an intractable problem. Over-expression of drug efflux transporters such as ABCB1, ABCC1 and ABCG2 contributes to it, by which they pump drugs out of cells, and result in the decrease in the efficacy of chemotherapy. To reverse the cancer MDR, we used 3-methyladenine (3-MA) treatment on taxol or doxorubicin stressed MDR cell lines A2780DX5 and SGC7091R and xeno-tumor implanted mice. The results indicate that ABCB1, ABCC1 and ABCG2 were depressed, and the PI3K-AKT-mTOR pathway was blocked. Moreover, using FITC-labeled taxol as the indicator, we observed that the drug accumulation was enhanced in MDR cells and more cells were killed after 3-MA administration. Thus suggesting that 3-MA can reverse cancer MDR via depressing agent-efflux transporters.
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Affiliation(s)
- Zhenyou Zou
- Institute of Tumor, Medical School, Taizhou University , Taizhou , China
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12
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Tsai ML, Chiou YS, Chiou LY, Ho CT, Pan MH. Garcinol suppresses inflammation-associated colon carcinogenesis in mice. Mol Nutr Food Res 2014; 58:1820-9. [PMID: 24981158 DOI: 10.1002/mnfr.201400149] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/07/2014] [Accepted: 05/11/2014] [Indexed: 01/04/2023]
Abstract
SCOPE Garcinol is a polyisoprenylated benzophenone derivative isolated from the fruit rind of Garcinia indica and has exhibited chemopreventive effects on azoxymethane)-induced colonic aberrant crypt foci in mice. In this study, we investigated whether garcinol protects against dextran sulfate sodium (DSS) induced colitis/inflammation and azoxymethane/DSS-induced inflammation-related colon tumorigenesis in male ICR mice. We also aimed to delineate the possible molecular mechanisms responsible for these effects. METHODS AND RESULTS Treatment with garcinol prevented shortening of the colon length and the formation of aberrant crypt foci and improved the inflammation score in the mouse colon stimulated by DSS. Moreover, administration of garcinol markedly decreased DSS-induced inducible nitric oxide synthase, cyclooxygenase-2, and proliferating cell nuclear antigen protein expression. The dietary administration of garcinol effectively reduced the tumor size and incidence in the mouse colon. Western blot and immunohistochemical analysis revealed that administration of garcinol significantly downregulated cyclooxygenase-2, cyclin D1, and vascular endothelial growth factor expression via inhibition of the extracellular signal-regulated protein kinase 1/2, phosphatidylinositol 3 kinase/Akt/p70 ribosomal S6 kinase, and Wnt/β-catenin signaling pathways. CONCLUSION Our results suggest that garcinol may merit further clinical investigation as a chemoprophylactic food that helps prevent colitis-associated colon cancer.
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Affiliation(s)
- Mei-Ling Tsai
- Department of Food Science, National Kaohsiung Marine University, Kaohsiung, Taiwan
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13
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Yang L, Wang R, Gao Y, Xu X, Fu K, Wang S, Li Y, Peng R. The protective role of interleukin-11 against neutron radiation injury in mouse intestines via MEK/ERK and PI3K/Akt dependent pathways. Dig Dis Sci 2014; 59:1406-14. [PMID: 24452839 DOI: 10.1007/s10620-013-3015-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/23/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Neutron irradiation (IR) has been proven to cause more serious damage than gamma IR. Preventing and curing neutron IR damage remains an urgent issue. AIMS The objective of this study was to investigate the radioprotective effects of IL-11 against neutron IR-induced damage in small intestine of mice. METHODS Mice were exposed to 3-Gy neutron IR whole body and then treated with 500 μg/kg interleukin-11 (IL-11) intraperitoneally every day. Mice were observed at various time-points over 1-5 days after IR. IEC-6 cells were exposed to 4 Gy neutron IR, and 100 ng/mL rhIL-11 was added to culture medium. Cell proliferation activity was estimated by MTT assay and rates of apoptosis were estimated by flow cytometry. RESULTS IL-11 slightly alleviated the incidence of diarrhea in the mice and promoted intestinal epithelia regeneration. In the in vitro study, neutron IR activated extracellular signal-regulated kinase (ERK)1/2 phosphorylation in intestinal epithelial cells constitutively, which was initially suppressed and then activated later by IL-11. The MEK-specific inhibitor U0126 could antagonize the positive effect of IL-11 on cell growth. Phosphatidylinositol 3-kinase (PI3K)/Akt pathway activation was suppressed after neutron IR, but could be triggered by IL-11 to protect the cells. The PI3K inhibitor LY294002 suppressed the positive effect of IL-11 on cell growth, and antagonized the protective effect of IL-11 against cell death after neutron IR. CONCLUSION IL-11 increases cell proliferation after neutron IR in MEK and PI3K-dependent signaling pathways, but protects cells against death only in the PI3K-dependent signaling pathway.
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Affiliation(s)
- Leilei Yang
- Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing, 100850, People's Republic of China
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Yang L, Wang R, Gao Y, Xu X, Fu K, Wang S, Li Y, Peng R, Hou X. The protective role of interleukin-11 against neutron radiation injury in mouse intestines via MEK/ERK and PI3K/Akt dependent pathways. Dig Dis Sci 2014. [PMID: 24452839 DOI: 10.1007/s10620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Neutron irradiation (IR) has been proven to cause more serious damage than gamma IR. Preventing and curing neutron IR damage remains an urgent issue. AIMS The objective of this study was to investigate the radioprotective effects of IL-11 against neutron IR-induced damage in small intestine of mice. METHODS Mice were exposed to 3-Gy neutron IR whole body and then treated with 500 μg/kg interleukin-11 (IL-11) intraperitoneally every day. Mice were observed at various time-points over 1-5 days after IR. IEC-6 cells were exposed to 4 Gy neutron IR, and 100 ng/mL rhIL-11 was added to culture medium. Cell proliferation activity was estimated by MTT assay and rates of apoptosis were estimated by flow cytometry. RESULTS IL-11 slightly alleviated the incidence of diarrhea in the mice and promoted intestinal epithelia regeneration. In the in vitro study, neutron IR activated extracellular signal-regulated kinase (ERK)1/2 phosphorylation in intestinal epithelial cells constitutively, which was initially suppressed and then activated later by IL-11. The MEK-specific inhibitor U0126 could antagonize the positive effect of IL-11 on cell growth. Phosphatidylinositol 3-kinase (PI3K)/Akt pathway activation was suppressed after neutron IR, but could be triggered by IL-11 to protect the cells. The PI3K inhibitor LY294002 suppressed the positive effect of IL-11 on cell growth, and antagonized the protective effect of IL-11 against cell death after neutron IR. CONCLUSION IL-11 increases cell proliferation after neutron IR in MEK and PI3K-dependent signaling pathways, but protects cells against death only in the PI3K-dependent signaling pathway.
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Affiliation(s)
- Leilei Yang
- Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing, 100850, People's Republic of China
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15
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Brown RE. Morphoproteomics: exposing protein circuitries in tumors to identify potential therapeutic targets in cancer patients. Expert Rev Proteomics 2014; 2:337-48. [PMID: 16000081 DOI: 10.1586/14789450.2.3.337] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Morphoproteomics combines the disciplines of histopathology, molecular biology and protein chemistry to paint a portrait of the protein circuitry in diseased cells for the purpose of uncovering molecular targets amenable to specific intervention, thereby customizing therapy for individual patients. This review considers the clinical application of morphoproteomics in malignant cells in the context of currently available pharmaceutical agents and discusses opportunities for combinatorial approaches that involve one or more small molecule inhibitors and single-agent chemotherapy with relatively low toxicity profiles. Future directions that involve focusing on points of convergence in signal transduction pathways and which integrate morphoproteomic with genomic and pharmacoproteomic and protein-function microarray data are offered.
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16
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Wong SH, Sung JJY, Chan FKL, To KF, Ng SSM, Wang XJ, Yu J, Wu WKK. Genome-wide association and sequencing studies on colorectal cancer. Semin Cancer Biol 2013; 23:502-11. [PMID: 24096009 DOI: 10.1016/j.semcancer.2013.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 09/24/2013] [Indexed: 12/28/2022]
Abstract
Colorectal cancer is a leading cause of morbidity and mortality worldwide. Understanding its genetic mechanisms is key to improving risk prediction, prognostication and treatment. Results from genome-wide association studies have engendered a growing list of colorectal cancer susceptibility genes whereas the application of genome-wide mutational analysis has enabled the depiction of mutational landscape of colorectal cancer at high resolution. The development of novel technologies, such as metagenomic and single-cell sequencing, is expected to have positive impact on future genetic studies. However, challenges remain to address the changing epidemiology of colorectal cancer, issues on genetic testing, and clinical utilization of genomic data.
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Affiliation(s)
- Sunny H Wong
- Institute of Digestive Disease and State Key Laboratory of Digestive Disease, Department of Medicine & Therapeutics and LKS Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong
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17
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Ciunci CA, Perini RF, Avadhani AN, Kang HC, Sun W, Redlinger M, Harlacker K, Flaherty KT, Giantonio BJ, Rosen MA, Divgi CR, Song HK, Englander S, Troxel A, Schnall M, O'Dwyer PJ. Phase 1 and pharmacodynamic trial of everolimus in combination with cetuximab in patients with advanced cancer. Cancer 2013; 120:77-85. [PMID: 24108668 DOI: 10.1002/cncr.28294] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 12/26/2022]
Abstract
BACKGROUND Preclinical and clinical studies suggest mTOR (mammalian target of rapamycin) inhibitors may have metabolic and antiangiogenic effects, and synergize with epidermal growth factor pathway inhibitors. Therefore, a phase 1/pharmacodynamic trial of everolimus with cetuximab was performed. METHODS A total of 29 patients were randomized to a run-in of oral everolimus (30, 50, or 70 mg) or cetuximab (400 mg/m(2) loading, 250 mg/m(2) maintenance) weekly, followed by the combination in this dose-escalation study. Primary endpoints were phase 2 dose and toxicity characterization. [(18)F]Fluorodeoxyglucose positron emission tomography (FDG-PET) was performed as a pharmacodynamic marker of mTOR inhibition, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed as an indicator of tumor perfusion changes, at 3 time points. RESULTS Everolimus and cetuximab were tolerable at full doses, with an expected toxicity profile. Dose-limiting toxicities in the everolimus 70 mg group included grade 3 skin toxicity in 2 patients, and mucositis in 1 patient. Of 16 patients evaluable for response, 5 had stable disease lasting 4 to 19 months. Mean change in maximum standardized uptake value (SUV(max)) for those treated initially with everolimus was -24% (2% to -54%), and with cetuximab was -5% (-23 to 36%). The K(trans) measured by DCE-MRI did not decrease, regardless of run-in drug. CONCLUSIONS Everolimus and cetuximab can be safely administered at standard doses, and are associated with prolonged disease control. The recommended phase 2 dose of oral weekly everolimus is 70 mg in combination with standard cetuximab. Imaging studies reveal that metabolic inhibition by everolimus alone and in combination with cetuximab predominates over changes in tumor perfusion in this patient population.
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Affiliation(s)
- Christine A Ciunci
- Abramson Cancer Center, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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18
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Wu WK, Wang XJ, Cheng AS, Luo MX, Ng SS, To KF, Chan FK, Cho CH, Sung JJ, Yu J. Dysregulation and crosstalk of cellular signaling pathways in colon carcinogenesis. Crit Rev Oncol Hematol 2013; 86:251-77. [DOI: 10.1016/j.critrevonc.2012.11.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 11/07/2012] [Accepted: 11/27/2012] [Indexed: 02/06/2023] Open
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Yu M, Grady WM. Therapeutic targeting of the phosphatidylinositol 3-kinase signaling pathway: novel targeted therapies and advances in the treatment of colorectal cancer. Therap Adv Gastroenterol 2012; 5:319-37. [PMID: 22973417 PMCID: PMC3437536 DOI: 10.1177/1756283x12448456] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the USA, and more effective treatment of CRC is therefore needed. Advances in our understanding of the molecular pathogenesis of this malignancy have led to the development of novel molecule-targeted therapies. Among the most recent classes of targeted therapies being developed are inhibitors targeting the phosphatidylinositol 3-kinase (PI3K) signaling pathway. As one of the most frequently deregulated pathways in several human cancers, including CRC, aberrant PI3K signaling plays an important role in the growth, survival, motility and metabolism of cancer cells. Targeting this pathway therefore has considerable potential to lead to novel and more effective treatments for CRC. Preclinical and early clinical studies have revealed the potential efficacy of drugs that target PI3K signaling for the treatment of CRC. However, a major challenge that remains is to study these agents in phase III clinical trials to see whether these early successes translate into better patient outcomes. In this review we focus on providing an up-to-date assessment of our current understanding of PI3K signaling biology and its deregulation in the molecular pathogenesis of CRC. Advances in available agents and challenges in targeting the PI3K signaling pathway in CRC treatment will be discussed and placed in the context of the currently available therapies for CRC.
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Affiliation(s)
- Ming Yu
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - William M. Grady
- Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N. D4-100, Seattle, WA 98109, USA; Department of Medicine, University of Washington Medical School, Seattle, WA, USA
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Ban K, Kozar RA. Protective role of p70S6K in intestinal ischemia/reperfusion injury in mice. PLoS One 2012; 7:e41584. [PMID: 22848534 PMCID: PMC3407246 DOI: 10.1371/journal.pone.0041584] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 06/25/2012] [Indexed: 12/20/2022] Open
Abstract
The mTOR signaling pathway plays a crucial role in the regulation of cell growth, proliferation, survival and in directing immune responses. As the intestinal epithelium displays rapid cell growth and differentiation and is an important immune regulatory organ, we hypothesized that mTOR may play an important role in the protection against intestinal ischemia reperfusion (I/R)-induced injury. To better understand the molecular mechanisms by which the mTOR pathway is altered by intestinal I/R, p70S6K, the major effector of the mTOR pathway, was investigated along with the effects of rapamycin, a specific inhibitor of mTOR and an immunosuppressant agent used clinically in transplant patients. In vitro experiments using an intestinal epithelial cell line and hypoxia/reoxygenation demonstrated that overexpression of p70S6K promoted cell growth and migration, and decreased cell apoptosis. Inhibition of p70S6K by rapamycin reversed these protective effects. In a mouse model of gut I/R, an increase of p70S6K activity was found by 5 min and remained elevated after 6 h of reperfusion. Inhibition of p70S6K by rapamycin worsened gut injury, promoted inflammation, and enhanced intestinal permeability. Importantly, rapamycin treated animals had a significantly increased mortality. These novel results demonstrate a key role of p70S6K in protection against I/R injury in the intestine and suggest a potential danger in using mTOR inhibitors in patients at risk for gut hypoperfusion.
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Affiliation(s)
- Kechen Ban
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.
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Zhou Y, Wang Q, Guo Z, Weiss HL, Evers BM. Nuclear factor of activated T-cell c3 inhibition of mammalian target of rapamycin signaling through induction of regulated in development and DNA damage response 1 in human intestinal cells. Mol Biol Cell 2012; 23:2963-72. [PMID: 22696685 PMCID: PMC3408422 DOI: 10.1091/mbc.e12-01-0037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Our results demonstrate that nuclear factor of activated T-cell 3 (NFATc3) contributes to the regulation of the mammalian target of rapamycin (mTOR) repressor regulated in development and DNA damage response 1 (REDD1) and mTOR downstream-targeted c-Myc expression. Furthermore, our study demonstrates a novel role for the NFATc3/REDD1/tuberous sclerosis complex 2 axis in the regulation of goblet cell differentiation. The nuclear factor of activated T-cell (NFAT) proteins are a family of transcription factors (NFATc1–c4) involved in the regulation of cell differentiation. We identified REDD1, a negative regulator of mammalian target of rapamycin (mTOR) through the tuberous sclerosis complex (TSC1/2 complex), as a new molecular target of NFATc3. We show that treatment with a combination of phorbol 12-myristate 13-acetate (PMA) plus ionophore A23187 (Io), which induces NFAT activation, increased REDD1 mRNA and protein expression and inhibited mTOR signaling; pretreatment with the calcineurin inhibitor cyclosporin A (CsA), an antagonist of NFAT signaling, decreased REDD1 induction and mTOR inhibition. Knockdown of NFATc3, not NFATc1, NFATc2, or NFATc4, attenuated PMA/Io-induced REDD1 expression. Treatment with PMA/Io increased REDD1 promoter activity and increased NFATc3 binding to the REDD1 promoter. Overexpression of NFATc3 increased REDD1 mRNA and protein expression and increased PMA/Io-mediated REDD1 promoter activity. Treatment with PMA/Io increased expression of the goblet cell differentiation marker MUC2; these changes were attenuated by pretreatment with CsA or knockdown of REDD1 or NFATc3. Overexpression of NFATc3 increased, while knockdown of TSC2 decreased, MUC2 expression. We provide evidence showing NFATc3 inhibits mTOR via induction of REDD1. Our results suggest a role for the NFATc3/REDD1/TSC2 axis in the regulation of intestinal cell differentiation.
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Affiliation(s)
- Yuning Zhou
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0293, USA
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22
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Takahashi H, Okamura D, Starr ME, Saito H, Evers BM. Age-dependent reduction of the PI3K regulatory subunit p85α suppresses pancreatic acinar cell proliferation. Aging Cell 2012; 11:305-14. [PMID: 22212451 DOI: 10.1111/j.1474-9726.2011.00787.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is important for tissue proliferation. Previously, we found that tissue regeneration after partial pancreatic resection was markedly attenuated in aged mice as compared to young mice and that this attenuation was because of an age-dependent reduction of PI3K/Akt signaling in the pancreatic acini; however, the mechanisms for the age-associated decline of pancreatic PI3K/Akt signaling remained unknown. To better delineate the mechanisms for the decreased PI3K/Akt activation with aging, age-associated changes in cell proliferation and PI3K/Akt signaling were investigated in the present study using in vitro primary pancreatic acinar cell cultures derived from young and aged mice. In response to treatment with insulin-like growth factor 1 (IGF-1), acinar cells from young but not aged mice showed increased activation of PI3K/Akt signaling and cell proliferation, indicating that intrinsic cellular mechanisms cause the age-associated changes in pancreatic acinar cells. We also found that the expression of PI3K p85α subunit, but not IGF-1 receptor or other PI3K subunits, was significantly reduced in pancreatic acinar cells from aged mice; this age-associated reduction of p85α was confirmed in both mouse and human pancreatic tissues. Finally, small interfering RNA (siRNA)-mediated knockdown of p85α expression in acinar cells from young mice resulted in markedly attenuated activation of PI3K/Akt downstream signaling in response to IGF-1. From these results, we conclude that exocrine pancreatic expression of PI3K p85α subunit is attenuated by aging, which is likely responsible for the age-associated decrease in activation of pancreatic PI3K signaling and acinar cell proliferation in response to growth-promoting stimuli.
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Affiliation(s)
- Hitoshi Takahashi
- Department of Surgery, University of Kentucky, Lexington, KY 40536, USA
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Abstract
Initially identified as the Caenorhabditis elegans PAR-4 homologue, the serine threonine kinase LKB1 is conserved throughout evolution and ubiquitously expressed. In humans, LKB1 is causally linked to the Peutz-Jeghers syndrome and is one of the most commonly mutated genes in several cancers like lung and cervical carcinomas. These observations have led to classify LKB1 as tumour suppressor gene. Although, considerable dark zones remain, an impressive leap in the understanding of LKB1 functions has been done during the last decade. Role of LKB1 as a major actor of the AMPK/mTOR pathway connecting cellular metabolism, cell growth and tumorigenesis has been extensively studied probably to the detriment of other functions of equal importance. This review will discuss about LKB1 activity regulation, its effectors and clues on their involvement in cell polarity.
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Buda A, Pignatelli M. E-cadherin and the cytoskeletal network in colorectal cancer development and metastasis. ACTA ACUST UNITED AC 2011; 18:133-43. [PMID: 22176698 DOI: 10.3109/15419061.2011.636465] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abnormalities in the expression and functional activity of cell adhesion molecules are implicated in the development and progression of the majority of colorectal cancers (CRC). Cell-cell adhesion molecule E-cadherin regulates cell polarity, differentiation, proliferation and migration through its intimate association to the actin cytoskeletal network. During colorectal carcinogenesis changes in intercellular adhesion and dynamic rearrangements in the actin cytoskeleton result in altered signalling and migration with loss of contact inhibition. The adenomatous polyposis coli (APC) protein, besides its established role in the β catenin/Wnt signalling pathway, can coordinate microtubule and actin organization during cell migration. The actin-bundling protein Fascin promotes cell motility and is overexpressed in CRC. Based on recent molecular and pathological studies, this review focusses on the role of these molecules sharing the common feature of being associated with the cytoskeletal network during colorectal carcinogenesis and metastasis. The potential use of these molecules as prognostic markers and/or therapeutic targets will also be discussed.
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Affiliation(s)
- Andrea Buda
- School of Clinical Sciences, University of Bristol, Bristol, UK
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25
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Feng Y, McDunn JE, Teitelbaum DH. Decreased phospho-Akt signaling in a mouse model of total parenteral nutrition: a potential mechanism for the development of intestinal mucosal atrophy. Am J Physiol Gastrointest Liver Physiol 2010; 298:G833-41. [PMID: 20299605 PMCID: PMC3774331 DOI: 10.1152/ajpgi.00030.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Total parenteral nutrition (TPN) leads to a decline in phosphatidylinositol 3-kinase (PI3K)/phospho-Akt (p-Akt) activity, affecting downstream signaling, reducing epithelial cell (EC) proliferation, and contributing to intestinal mucosal atrophy. We hypothesized that promoting Akt activity would prevent these changes. We used a novel Akt-activating peptide, TCL1 (a head-to-tail dimer of the Akt-binding domain of T-cell lymphoma-1), or an inactive mutant sequence TCL1G conjugated to a transactivator of transcription peptide sequence to promote intracellular uptake. Four groups of mice were studied, enteral nutrition group (control), control mice given a functioning TCL1 (control + TCL1), TPN mice given TCL1G (control peptide, TPN + TCL1G); and TPN mice given TCL1. TPN mice given TCL1G showed a significant decrease in jejunal EC p-Akt (Ser473 and Thr308) abundance, whereas TPN + TCL1 mice showed increased p-Akt (Ser473) abundance. Phosphorylation of beta-catenin and glycogen synthase kinase-3beta (downstream targets of Akt signaling) were also decreased in the TPN + TCL1G group and completely prevented in the TPN + TCL1 group. Use of TCL1 nearly completely prevented the decline in EC proliferation seen in the TPN + TCL1G group, as well as partly returned EC apoptosis levels close to controls. The mammalian target of rapamycin pathway demonstrated a similar reduction in activity in the TPN + TCL1G group that was significantly prevented in the TPN + TCL1 group. These results support a significant loss of PI3K/p-Akt signaling upon replacing enteral nutrition with TPN, and prevention of this loss demonstrates the key importance of PI3K/p-Akt signaling in maintaining gut integrity including EC proliferation and reduction in apoptosis.
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Affiliation(s)
- Yongjia Feng
- 1Section of Pediatric Surgery, Department of Surgery, the University of Michigan Medical School and the C. S. Mott Children's Hospital, Ann Arbor, Michigan;
| | - Jonathan E. McDunn
- 2Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri
| | - Daniel H. Teitelbaum
- 1Section of Pediatric Surgery, Department of Surgery, the University of Michigan Medical School and the C. S. Mott Children's Hospital, Ann Arbor, Michigan;
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Robert F, Pelletier J. Translation initiation: a critical signalling node in cancer. Expert Opin Ther Targets 2009; 13:1279-93. [PMID: 19705976 DOI: 10.1517/14728220903241625] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a master regulator of translation initiation that controls the recruitment of ribosomes to mRNA templates in response to intracellular and extracellular cues. Evidence suggests that mTOR and its direct downstream targets, S6K and eIF4E/4E-BP, play significant roles in oncogenesis, and that inhibiting this pathway holds promise as an anti-proliferative approach. Recent genome-wide analyses of mutations in human cancers indicate that transformed cells activate a handful of processes and signalling pathways that are major contributors to their phenotype. Here we review the current literature implicating mTOR and translation initiation downstream of many of these various signalling pathways and processes usurped in human cancers. This review highlights the widespread activation of mTOR/eIF4E following acquisition of oncogenic lesions and its implication in promoting the transformation phenotype and indicates that targeting the control of translation initiation makes logical sense as a broad-acting therapeutic approach.
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Affiliation(s)
- Francis Robert
- Department of Biochemistry and Goodman cancer centre, McGill University, McIntyre Medical Sciences Building, Room 810, 3655 Promenade Sir William Osler, Montreal, Quebec, H3G 1Y6, Canada
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Wu WKK, Volta V, Cho CH, Wu YC, Li HT, Yu L, Li ZJ, Sung JJY. Repression of protein translation and mTOR signaling by proteasome inhibitor in colon cancer cells. Biochem Biophys Res Commun 2009; 386:598-601. [DOI: 10.1016/j.bbrc.2009.06.080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 06/15/2009] [Indexed: 01/22/2023]
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Auyeung KKW, Cho CH, Ko JKS. A novel anticancer effect of Astragalus saponins: Transcriptional activation of NSAID-activated gene. Int J Cancer 2009; 125:1082-91. [PMID: 19384947 DOI: 10.1002/ijc.24397] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Astragalus membranaceus has been used to ameliorate the side effects of antineoplastic drugs because of its immunomodulating nature. We had recently demonstrated that total Astragalus saponins (AST) possess anticarcinogenic and proapoptotic properties in human colon cancer cells and tumor xenograft. In this study, we identified NSAID-activated gene (NAG-1) as a potential molecular target of AST. The growth-inhibitory and proapoptotic effects of AST were assessed in a panel of human cancer cell lines. Hoechst 33342 nuclear staining, Annexin V-FITC/propidium iodide staining, Western immunoblotting, real-time PCR, luciferase reporter assay and electrophoretic mobility shift assay were conducted to determine the association of NAG-1 and related transcription factors with AST during its regulation of apoptotic activities. Moreover, the combined proapoptotic and NAG-1 promoting activities of AST and/or inhibitors of the PI3K-Akt pathway were also examined. AST caused overexpression of NAG-1, leading to PARP cleavage and apoptosis. The induction of NAG-1 promoter activity by the drug was associated with increased gene expression, in addition to prior increase in Egr-1 expression and DNA binding activity. AST-induced NAG-1 activation was intensified when PI3K inhibitor LY294002 or Akt inhibitor was co-treated and reversed by NAG-1 siRNA transfection. Nevertheless, the extent of NAG-1 induction could not be altered by the ERK inhibitor PD98059. Our results indicate that NAG-1 is a potential molecular target of AST in its antitumorigenic and proapoptotic actions, which would have additive effects when used along with PI3K-Akt inhibitors. The information obtained could facilitate future development of a novel target-specific chemotherapeutic agent with known molecular pathway.
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Fernández de Mattos S, Villalonga P, Clardy J, Lam EWF. FOXO3a mediates the cytotoxic effects of cisplatin in colon cancer cells. Mol Cancer Ther 2008; 7:3237-46. [PMID: 18852127 DOI: 10.1158/1535-7163.mct-08-0398] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cisplatin is a conventional chemotherapeutic agent that binds covalently to purine DNA bases and mediates cellular apoptosis. A better understanding of the downstream cellular targets of cisplatin will provide information on its mechanism of action and help to understand the mechanism of drug resistance. In this study, we have investigated the effects of cisplatin in a panel of colon carcinoma cell lines and the involvement of the phosphoinositide-3-kinase/forkhead/winged helix box class O (FOXO) pathway in cisplatin action and resistance. Cisplatin-sensitive and cisplatin-resistant cell lines have been characterized in cell viability, flow cytometry, and clonogenic assays. The main components of the phosphoinositide-3-kinase/protein kinase B pathway, particularly FOXO3a, have been analyzed in sensitive and resistant cells on cisplatin treatment. Interestingly, in sensitive cells, cisplatin induces FOXO3a dephosphorylation and nuclear translocation, and expression of its target genes, whereas in resistant cells the effect of cisplatin on FOXO3a is incomplete. Consistent with this, protein kinase B/FOXO signaling axis modulators triciribine and psammaplysene A sensitize the resistant HT29 cells to cisplatin treatment. Critically, knockdown of FOXO3a expression using small interfering RNA rescues sensitive SW620 cells from cisplatin-induced short- and long-term cell death. Together, our findings suggest that FOXO3a is a relevant mediator of the cytotoxic effects of cisplatin in colon cancer cells.
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Affiliation(s)
- Silvia Fernández de Mattos
- Cancer Cell Biology Group, Institut Universitari d'Investigació en Ciències de la Salut, Departament de Biologia Fonamental, Universitat de les Illes Balears, Crta Valldemossa km 7.5, E-07122 Palma, Illes Balears, Spain.
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Inhibition of the mTORC1 pathway suppresses intestinal polyp formation and reduces mortality in ApcDelta716 mice. Proc Natl Acad Sci U S A 2008; 105:13544-9. [PMID: 18768809 DOI: 10.1073/pnas.0800041105] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth via mTOR complex 1 (mTORC1), whose activation has been implicated in many human cancers. However, mTORC1's status in gastrointestinal tumors has not been characterized thoroughly. We have found that the mTORC1 pathway is activated with increased expression of the mTOR protein in intestinal polyps of the Apc(Delta716) heterozygous mutant mouse, a model for human familial adenomatous polyposis. An 8-week treatment with RAD001 (everolimus) suppressed the mTORC1 activity in these polyps and inhibited proliferation of the adenoma cells as well as tumor angiogenesis, which significantly reduced not only the number of polyps but also their size. beta-Catenin knockdown in the colon cancer cell lines reduced the mTOR level and thereby inhibited the mTORC1 signaling. These results suggest that the Wnt signaling contributes to mTORC1 activation through the increased level of mTOR and that the activation plays important roles in the intestinal polyp formation and growth. Indeed, long-term RAD001 treatment significantly reduced mortality of the Apc(Delta716) mice. Thus, we propose that the mTOR inhibitors may be efficacious for therapy and prevention of colonic adenomas and cancers with Wnt signaling activation.
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Limaye PB, Bowen WC, Orr AV, Luo J, Tseng GC, Michalopoulos GK. Mechanisms of hepatocyte growth factor-mediated and epidermal growth factor-mediated signaling in transdifferentiation of rat hepatocytes to biliary epithelium. Hepatology 2008; 47:1702-13. [PMID: 18398918 PMCID: PMC2615562 DOI: 10.1002/hep.22221] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
UNLABELLED Previous studies from our laboratory have demonstrated that hepatocytes can transdifferentiate into biliary epithelium (BE) both in vivo and in vitro; however, the mechanisms are unclear. The current study was designed to investigate the mechanisms of hepatocyte transdifferentiation in vitro. Rat hepatocytes were cultured in roller bottles to obtain hepatocyte organoid cultures, which were stimulated with various growth factors (GFs) including hepatocyte growth factor (HGF), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), stem cell factor (SCF), macrophage-stimulating protein (MSP), fibroblast growth factor-a (FGF-a), fibroblast growth factor-b (FGF-b), and fibroblast growth factor-8b (FGF-8b). Only the cultures treated with HGF, EGF, and their combination exhibited formation of hepatocyte-derived biliary epithelium (BE) despite the presence and activation of all the pertinent cognate membrane receptors of the rest of the GFs. Microarray analysis of the organoid cultures identified specific up-regulation of approximately 500 target genes induced by HGF and EGF, including members of the extracellular matrix (ECM) protein family, Wnt/beta-catenin pathway, transforming growth factor beta (TGF-beta)/bone morphogenetic protein (BMP) pathway, and CXC (cysteine-any amino acid-cysteine) chemokines. To investigate the downstream signaling involved in hepatocyte to biliary epithelial cell (BEC) transdifferentiation, we investigated expression and activities of mitogen-activated protein (MAP) kinases [extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK)] as well as serine/threonine kinase AKT. The analysis indicated that AKT phosphorylation was particularly increased in cultures treated with HGF, EGF, and their combination. Whereas phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 completely inhibited biliary epithelium formation, AKT inhibitor could only moderately reduce formation of BE in the organoid cultures treated with HGF+EGF. Most of the HGF+EGF target genes were altered by LY294002. CONCLUSION Taken together, these data indicate that hepatocyte to BE transdifferentiation is regulated by HGF and EGF receptors and that PI3 kinase-mediated signaling independent of AKT is a crucial component of the transdifferentiation process.
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Affiliation(s)
- Pallavi B. Limaye
- Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - William C. Bowen
- Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Anne V. Orr
- Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jianhua Luo
- Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - George C. Tseng
- Department of Biostatistics and Human Genetics, Graduate School of Public Health, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - George K. Michalopoulos
- Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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Potentiation of antileukemic therapies by the dual PI3K/PDK-1 inhibitor, BAG956: effects on BCR-ABL- and mutant FLT3-expressing cells. Blood 2008; 111:3723-34. [PMID: 18184863 DOI: 10.1182/blood-2007-09-114454] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mediators of PI3K/AKT signaling have been implicated in chronic myeloid leukemia (CML) and acute myeloid leukemia (AML). Studies have shown that inhibitors of PI3K/AKT signaling, such as wortmannin and LY294002, are able to inhibit CML and AML cell proliferation and synergize with targeted tyrosine kinase inhibitors. We investigated the ability of BAG956, a dual PI3K/PDK-1 inhibitor, to be used in combination with inhibitors of BCR-ABL and mutant FLT3, as well as with the mTOR inhibitor, rapamycin, and the rapamycin derivative, RAD001. BAG956 was shown to block AKT phosphorylation induced by BCR-ABL-, and induce apoptosis of BCR-ABL-expressing cell lines and patient bone marrow cells at concentrations that also inhibit PI3K signaling. Enhancement of the inhibitory effects of the tyrosine kinase inhibitors, imatinib and nilotinib, by BAG956 was demonstrated against BCR-ABL expressing cells both in vitro and in vivo. We have also shown that BAG956 is effective against mutant FLT3-expressing cell lines and AML patient bone marrow cells. Enhancement of the inhibitory effects of the tyrosine kinase inhibitor, PKC412, by BAG956 was demonstrated against mutant FLT3-expressing cells. Finally, BAG956 and rapamycin/RAD001 were shown to combine in a nonantagonistic fashion against BCR-ABL- and mutant FLT3-expressing cells both in vitro and in vivo.
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Shen X, Rychahou PG, Evers BM, Falzon M. PTHrP increases xenograft growth and promotes integrin alpha6beta4 expression and Akt activation in colon cancer. Cancer Lett 2007; 258:241-52. [PMID: 17964713 PMCID: PMC2180421 DOI: 10.1016/j.canlet.2007.09.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 09/05/2007] [Accepted: 09/11/2007] [Indexed: 11/23/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) is expressed by human colon cancer tissue and cell lines. Expression of PTHrP and phosphatidylinositol 3-kinase (PI3-K) pathway components correlates with the severity of colon carcinoma. Here we observed a positive effect of endogenous PTHrP on LoVo (human colon cancer) cell proliferation, migration, invasion, integrin alpha6 and beta4 expression, and p-Akt levels. There was a direct correlation between PTHrP expression and anchorage-independent cell growth. PTHrP significantly increased xenograft growth; tumors from PTHrP-overexpressing cells showed increased expression of integrins alpha6 and beta4, and PI3-K pathway components. The higher expression of PTHrP in human colon cancer adenocarcinoma vs. normal colonic mucosa was accompanied by increased integrin alpha6 and beta4 levels. Elevated PTHrP expression in colon cancer may thus upregulate integrin alpha6beta4 expression, with consequent PI3-K activation. Targeting PTHrP might result in effective inhibition of tumor growth, migration, and invasion.
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Affiliation(s)
- Xiaoli Shen
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555
| | - Piotr G. Rychahou
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555
| | - B. Mark Evers
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555
- Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, Galveston, TX 77555
| | - Miriam Falzon
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555
- Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, Galveston, TX 77555
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Basuroy UK, Gerner EW. Emerging concepts in targeting the polyamine metabolic pathway in epithelial cancer chemoprevention and chemotherapy. J Biochem 2007; 139:27-33. [PMID: 16428316 DOI: 10.1093/jb/mvj022] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The polyamines are important molecules governing cell proliferation, survival and apoptosis. Consistent with their elevated levels in cancer, they have been shown to mediate tumor promotion and progression. Cellular and tissue polyamine pools and metabolic flux are regulated by a number of processes. Neoplastic transformation is accompanied with an increase in biosynthesis, decreased catabolism and elevated uptake of exogenous polyamines. Effective strategies for cancer chemoprevention and chemotherapy, targeting the polyamine metabolic pathway will likely require a combination of agents acting at multiple sites of this pathway. Genetic variability affecting expression of the ornithine decarboxylase gene suggests an association between ODC expression and cancer risk, and prediction of response to treatment in certain epithelial cancers.
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Affiliation(s)
- Upal K Basuroy
- Biochemistry and Molecular and Cellular Biology Gradaute Program, University of Arizona, Tucson, AZ 85724, USA
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Winbanks CE, Grimwood L, Gasser A, Darby IA, Hewitson TD, Becker GJ. Role of the phosphatidylinositol 3-kinase and mTOR pathways in the regulation of renal fibroblast function and differentiation. Int J Biochem Cell Biol 2007; 39:206-19. [PMID: 16973406 DOI: 10.1016/j.biocel.2006.08.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 07/31/2006] [Accepted: 08/08/2006] [Indexed: 11/19/2022]
Abstract
Tubulointerstitial fibrosis is largely mediated by (myo)fibroblasts present in the interstitium. In this study, we investigated the role of mTOR and phosphatidylinositol 3-kinase in the regulation of fibroblast kinetics, fibroblast differentiation, and collagen synthesis. Rat renal fibroblasts were propagated from kidneys 3 days post-ureteric obstruction and specific inhibitors of mTOR (RAD) and phosphatidylinositol 3-kinase (LY294002) were used to examine the regulation of fibrogenesis. LY294002 but not RAD completely inhibited phosphorylation of Akt, while both inhibitors decreased phosphorylation of the S6 ribosomal protein. RAD and LY decreased foetal calf serum stimulated proliferation and DNA synthesis. In addition to their individual effects, treatment with both RAD and LY294002 decreased serum-induced fibroblast proliferation and DNA synthesis significantly more than either drug alone. TUNEL positive cells (apoptosis) in RAD and LY294002 treated groups were not different from control groups. In addition to their effect on proliferation, both inhibitors also reduced total collagen synthesis. Differentiation studies indicated an increase in alpha-smooth muscle actin expression relative to beta-actin (western blotting), with cytochemistry confirming that all doses of RAD and LY294002 increased the proportion of alpha-smooth muscle actin positive cells, and hence myofibroblasts. Effects were independent of cell toxicity. These results highlight the potential significance of PI3K and mTOR, in the regulation of renal (myo)fibroblast activity. The synergistic effects of LY and RAD on proliferation suggest that mTOR signalling involves pathways other than phosphatidylinositol 3-kinase. These results provide a novel insight into the mechanisms of fibroblast regulation during fibrogenesis.
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Affiliation(s)
- Catherine E Winbanks
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic. 3050, Australia
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Zhang L, Li J, Young LH, Caplan MJ. AMP-activated protein kinase regulates the assembly of epithelial tight junctions. Proc Natl Acad Sci U S A 2006; 103:17272-7. [PMID: 17088526 PMCID: PMC1859922 DOI: 10.1073/pnas.0608531103] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
AMP activated protein kinase (AMPK), a sensor of cellular energy status in all eukaryotic cells, is activated by LKB1-dependent phosphorylation. Recent studies indicate that activated LKB1 induces polarity in epithelial cells and that this polarization is accompanied by the formation of tight junction structures. We wished to determine whether AMPK also contributes to the assembly of tight junctions in the epithelial cell polarization process. We found that AMPK is activated during calcium-induced tight junction assembly. Activation of AMPK by 5-aminoimidazole-4-carboxamide ribonucleoside facilitates tight junction assembly under conditions of normal extracellular Ca2+ concentrations and initiates tight junction assembly in the absence of Ca2+ as revealed by the relocation of zonula occludens 1, the establishment of transepithelial electrical resistance, and the paracellular flux assay. Expression of a dominant negative AMPK construct inhibits tight junction assembly in MDCK cells, and this defect in tight junction assembly can be partially ameliorated by rapamycin. These results suggest that AMPK plays a role in the regulation of tight junction assembly.
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Affiliation(s)
| | - Ji Li
- Department of Internal Medicine, Section of Cardiovascular Medicine, and
| | - Lawrence H. Young
- Department of Internal Medicine, Section of Cardiovascular Medicine, and
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Michael J. Caplan
- *Department of Cell Biology
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
- To whom correspondence should be addressed at:
Department of Cellular and Molecular Physiology, Yale University School of Medicine, P.O. Box 208026, New Haven, CT 06520-8026. E-mail:
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Kawabata K, Murakami A, Ohigashi H. Citrus auraptene targets translation of MMP-7 (matrilysin) via ERK1/2-dependent and mTOR-independent mechanism. FEBS Lett 2006; 580:5288-94. [PMID: 16979634 DOI: 10.1016/j.febslet.2006.08.072] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 08/25/2006] [Accepted: 08/31/2006] [Indexed: 11/22/2022]
Abstract
Matrix metalloproteinase (MMP)-7 is considered to play essential roles in cancer progression. We examined the efficacy of auraptene, a citrus coumarin derivative, for suppressing MMP-7 expression in the human colorectal adenocarcinoma cell line HT-29. Auraptene remarkably inhibited the production of proMMP-7 protein, without affecting its mRNA expression level. Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), showed similar results, suggesting that auraptene suppresses mTOR-dependent proMMP-7 translation. Interestingly, however, auraptene showed no effects on the activation of Akt/mTOR signaling, whereas the phosphorylation levels of 4E binding protein (4EBP)1 and eukaryotic translation initiation factor (eIF)4B were substantially decreased. In addition, auraptene remarkably dephosphorylated constitutively activated extracellular signal-regulated kinase (ERK)1/2. Transfection of ERK1/2 siRNA led to a significant reduction of proMMP-7 protein production as well as of the phosphorylation of eIF4B. These results demonstrate that auraptene targets the translation step for proMMP-7 protein synthesis by disrupting ERK1/2-mediated phosphorylation of 4EBP1 and eIF4B.
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Affiliation(s)
- Kyuichi Kawabata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Arvisais EW, Romanelli A, Hou X, Davis JS. AKT-independent phosphorylation of TSC2 and activation of mTOR and ribosomal protein S6 kinase signaling by prostaglandin F2alpha. J Biol Chem 2006; 281:26904-13. [PMID: 16816403 DOI: 10.1074/jbc.m605371200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prostaglandin F2alpha (PGF2alpha) is an important mediator of corpus luteum (CL) regression, although the cellular signaling events that mediate this process have not been clearly identified. It is established that PGF2alpha binds to a G-proteincoupled receptor (GPCR) to stimulate protein kinase C (PKC) and Raf-MEK-Erk signaling in luteal cells. The present experiments were performed to determine whether PGF2alpha stimulates the mammalian target of rapamycin (mTOR)/ribosomal protein S6 kinase 1 (S6K1) signaling pathway in steroidogenic luteal cells. We demonstrate that PGF2alpha treatment results in a timeand concentration-dependent stimulation of the phosphorylation and activation of S6K1. The stimulation of S6K1 in response to PGF2alpha treatment was abolished by the mTOR inhibitor rapamycin. Treatment with PGF2alpha did not increase AKT phosphorylation but increased the phosphorylation of Erk and the tumor suppressor protein tuberous sclerosis complex 2 (TSC2), an upstream regulator of mTOR. The effects of PGF2alpha were mimicked by the PKC activator PMA and inhibited by U0126, a MEK1 inhibitor. The activation of mTOR/S6K1 and putative down stream processes involving the translational apparatus (i.e. 4EBP1 phosphorylation, release of 4EBP1 binding in m(7)G cap binding assays, and the phosphorylation and synthesis of S6) were completely sensitive to treatment with rapamycin, implicating mTOR in the actions of PGF2alpha. Taken together, our data suggest that GPCR activation in response to PGF2alpha stimulates the mTOR pathway which increases the translational machinery in luteal cells. The translation of proteins under the control of mTOR may have implications for luteal development and regression and offer new strategies for therapeutic intervention in PGF2alpha-target tissues.
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Affiliation(s)
- Edward W Arvisais
- Olson Center for Women's Health, Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, Nebraska 68198-3255, USA
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Rychahou PG, Jackson LN, Silva SR, Rajaraman S, Evers BM. Targeted molecular therapy of the PI3K pathway: therapeutic significance of PI3K subunit targeting in colorectal carcinoma. Ann Surg 2006; 243:833-42; discussion 843-4. [PMID: 16772787 PMCID: PMC1570577 DOI: 10.1097/01.sla.0000220040.66012.a9] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The phosphatidylinositol 3-kinase (PI3K) pathway promotes cancer cell proliferation and survival. The authors determined the pattern of distribution of PI3K pathway components (ie, the p85alpha regulatory subunit, p110alpha catalytic subunit, Akt1, Akt2, and the tumor suppressor PTEN) in human colorectal cancer. In addition, inhibition of in vitro proliferation and in vivo liver metastasis by p85alpha or p110alpha siRNA treatment was analyzed. SUMMARY BACKGROUND DATA Small interfering RNA (siRNA) molecules suppress expression of target genes and may have therapeutic applications as target-specific therapies for cancer. Therefore, the purpose of this study was 2-fold: 1) to analyze the distribution pattern of PI3K pathway components in human normal colorectal cancers, and 2) to determine whether targeted inhibition of PI3K inhibits colon cancer growth in vitro and suppresses metastatic growth in vivo. METHODS Immunohistochemical analysis was performed on colorectal adenocarcinomas and adjacent normal mucosa for PI3K pathway components, including p85alpha, p110alpha, Akt1, Akt2, and the tumor suppressor PTEN, which inhibits PI3K. HT29 and KM20 human colon cancer cells were treated with siRNA directed to p85alpha or p110alpha, and cell viability and apoptosis assessed. HT29 cells, transfected with a plasmid containing green fluorescent protein (GFP), were injected into the spleen of athymic nude mice to establish liver metastases; mice were randomized to receive either nontargeting control (NTC), p85alpha or p110alpha siRNA. RESULTS PI3K pathway components p85alpha and Akt2 were highly expressed in glandular elements of colon cancers, with a correlation between staining intensity and clinical stage; PTEN expression was decreased in the colon cancers of all stages. PI3K-specific siRNA treatment decreased cell viability in vitro and suppressed metastatic tumor growth in vivo. CONCLUSIONS Selective targeting of PI3K pathway components may enhance the effects of standard chemotherapeutic agents and provide novel adjuvant treatment of selected colorectal cancers.
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Affiliation(s)
- Piotr G Rychahou
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555, USA
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Guerriero R, Parolini I, Testa U, Samoggia P, Petrucci E, Sargiacomo M, Chelucci C, Gabbianelli M, Peschle C. Inhibition of TPO-induced MEK or mTOR activity induces opposite effects on the ploidy of human differentiating megakaryocytes. J Cell Sci 2006; 119:744-52. [PMID: 16449323 DOI: 10.1242/jcs.02784] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The megakaryocyte is a paradigm for mammalian polyploid cells. However, the mechanisms underlying megakaryocytic polyploidization have not been elucidated. In this study, we investigated the role of Shc-Ras-MAPK and PI3K-AKT-mTOR pathways in promoting megakaryocytic differentiation, maturation and polyploidization. CD34+ cells, purified from human peripheral blood, were induced in serum-free liquid suspension culture supplemented with thrombopoietin (TPO) to differentiate into a virtually pure megakaryocytic progeny (97-99% CD61+/CD41+ cells). The early and repeated addition to cell cultures of low concentrations of PD98059, an inhibitor of MEK1/2 activation, gave rise to a population of large megakaryocytes showing an increase in DNA content and polylobated nuclei (from 45% to 70% in control and treated cultures, respectively). Conversely, treatment with the mTOR inhibitor rapamycin strongly inhibited cell polyploidization, as compared with control cultures. Western blot analysis of PD98059-treated progenitor cells compared with the control showed a downmodulation of phospho-ERK 1 and phospho-ERK 2 and a minimal influence on p70S6K activation; by contrast, p70S6K activation was completely inhibited in rapamycin-treated cells. Interestingly, the cyclin D3 localization was nuclear in PD98059-induced polyploid megakaryocytes, whereas it was completely cytoplasmic in those treated with rapamycin. Altogether, our results are in line with a model in which binding of TPO to the TPO receptor (mpl) could activate the rapamycin-sensitive PI3K-AKT-mTOR-p70S6K pathway and its downstream targets in promoting megakaryocytic cell polyploidization.
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Affiliation(s)
- Raffaella Guerriero
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
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Bedogni B, Welford SM, Cassarino DS, Nickoloff BJ, Giaccia AJ, Powell MB. The hypoxic microenvironment of the skin contributes to Akt-mediated melanocyte transformation. Cancer Cell 2005; 8:443-54. [PMID: 16338658 DOI: 10.1016/j.ccr.2005.11.005] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 10/25/2005] [Accepted: 11/16/2005] [Indexed: 12/21/2022]
Abstract
Constitutive activation of Akt characterizes a high percentage of human melanomas and represents a poor prognostic factor of the disease. We show that Akt transforms melanocytes only in a hypoxic environment, which is found in normal skin. The synergy between Akt and hypoxia is HIF1alpha mediated. Inhibition of HIF1alpha decreases Akt transformation capacity in hypoxia and tumor growth in vivo, while overexpression of HIF1alpha allows anchorage-independent growth in normoxia and development of more aggressive tumors. Finally, we show that mTOR activity is necessary to maintain the transformed phenotype by sustaining HIF1alpha activity. Taken together, these findings demonstrate that Akt hyperactivation and HIF1alpha induction by normally occurring hypoxia in the skin significantly contribute to melanoma development.
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Affiliation(s)
- Barbara Bedogni
- Division of Radiation and Cancer Biology, Stanford University, Stanford, California 94305, USA
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Friday BB, Adjei AA. K-ras as a target for cancer therapy. Biochim Biophys Acta Rev Cancer 2005; 1756:127-44. [PMID: 16139957 DOI: 10.1016/j.bbcan.2005.08.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 07/29/2005] [Accepted: 08/01/2005] [Indexed: 11/30/2022]
Abstract
The central role K-, H- and N-Ras play in regulating diverse cellular pathways important for cell growth, differentiation and survival is well established. Dysregulation of Ras proteins by activating mutations, overexpression or upstream activation is common in human tumors. Of the Ras proteins, K-ras is the most frequently mutated and is therefore an attractive target for cancer therapy. The complexity of K-ras signaling presents many opportunities for therapeutic targeting. A number of different approaches aimed at abrogating K-ras activity have been explored in clinical trials. Several of the therapeutic agents tested have demonstrated clinical activity, supporting ongoing development of K-ras targeted therapies. However, many of the agents currently being evaluated have multiple targets and their antitumor effects may not be due to K-Ras inhibition. To date, no selective, specific inhibitor of K-ras is available for routine clinical use. In this review, we will summarize the structure and function of K-ras with attention to its role in tumorigenesis and discuss the successes and failures of the various strategies designed to therapeutically target this important oncogene.
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Affiliation(s)
- Bret B Friday
- Division of Medical Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Dasgupta B, Yi Y, Chen DY, Weber JD, Gutmann DH. Proteomic analysis reveals hyperactivation of the mammalian target of rapamycin pathway in neurofibromatosis 1-associated human and mouse brain tumors. Cancer Res 2005; 65:2755-60. [PMID: 15805275 DOI: 10.1158/0008-5472.can-04-4058] [Citation(s) in RCA: 216] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Individuals with the tumor predisposition syndrome, neurofibromatosis 1 (NF1), are prone to development of nervous system tumors, including neurofibromas and pilocytic astrocytomas. Based on the ability of the NF1 gene product (neurofibromin) to function as a GTPase activating protein for RAS, initial biologically based therapies for NF1-associated tumors focused on the use of RAS inhibitors, but with limited clinical success. In an effort to identify additional targets for therapeutic drug design in NF1, we used an unbiased proteomic approach to uncover unanticipated intracellular signaling pathways dysregulated in Nf1-deficient astrocytes. We found that the expression of proteins involved in promoting ribosome biogenesis was increased in the absence of neurofibromin. In addition, Nf1-deficient astrocytes exhibit high levels of mammalian target of rapamycin (mTOR) pathway activation, which was inhibited by blocking K-RAS or phosphatidylinositol 3-kinase activation. This mTOR pathway hyperactivation was reflected by high levels of ribosomal S6 activation in both Nf1 mutant mouse optic nerve gliomas and in human NF1-associated pilocytic astrocytoma tumors. Moreover, inhibition of mTOR signaling in Nf1-/- astrocytes abrogated their growth advantage in culture, restoring normal proliferative rates. These results suggest that mTOR pathway inhibition may represent a logical and tractable biologically based therapy for brain tumors in NF1.
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Affiliation(s)
- Biplab Dasgupta
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
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Watanabe H, Saito H, Rychahou PG, Uchida T, Evers BM. Aging is associated with decreased pancreatic acinar cell regeneration and phosphatidylinositol 3-kinase/Akt activation. Gastroenterology 2005; 128:1391-404. [PMID: 15887120 DOI: 10.1053/j.gastro.2005.03.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS The effects of aging on pancreatic acinar cell proliferation have not been clearly defined. Phosphatidylinositol 3-kinase (PI3K)-mediated phosphorylation of Akt is a critical step for proliferation of various cell types and insulin secretion from pancreatic endocrine cells; however, its role in acinar cell proliferation is not known. The purpose of this study was to (1) delineate the effects of aging on pancreatic regeneration after partial pancreatectomy (Px) and (2) define the involvement of the PI3K/Akt pathway in pancreatic regeneration. METHODS Following partial Px, pancreatic regeneration and activation of the PI3K pathway were compared in young and aged mice. Activation of the PI3K/Akt pathway was evaluated by Akt phosphorylation (pAkt). The role of the PI3K pathway in pancreatic regeneration after partial Px was assessed by effects of a pharmacologic PI3K inhibitor wortmannin or small interfering RNA (siRNA) to the p85alpha regulatory subunit. To confirm further the critical role of the PI3K/Akt pathway in pancreatic acinar cell proliferation, IGF-1-mediated cell proliferation was determined in cultured acinar cells pretreated with wortmannin or p85alpha siRNA. RESULTS Pancreatic regeneration and pAkt expression after partial Px were significantly decreased with aging. Treatment with wortmannin or p85alpha siRNA reduced pancreatic regeneration after partial Px. The IGF-1-mediated cell proliferation in vitro was completely blocked by wortmannin or p85alpha siRNA but not by the MEK/ERK inhibitor PD98059. CONCLUSIONS PI3K/Akt activation plays a critical role in the regeneration of pancreatic acini after resection. Furthermore, pancreatic regeneration is markedly attenuated in the aged pancreas most likely because of decreased PI3K/Akt activation.
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Affiliation(s)
- Hiroaki Watanabe
- Department of Surgery, The University of Texas Medical Branch, Galveston 77555-0536, USA
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Buchanan FG, McReynolds M, Couvillon A, Kam Y, Holla VR, Dubois RN, Exton JH. Requirement of phospholipase D1 activity in H-RasV12-induced transformation. Proc Natl Acad Sci U S A 2005; 102:1638-42. [PMID: 15668389 PMCID: PMC547811 DOI: 10.1073/pnas.0406698102] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The ability of the Ras oncogene to transform normal cells has been well established. One downstream effector of Ras is the lipid hydrolyzing enzyme phospholipase D. Recent evidence has emerged indicating a role for phospholipase D in cell proliferation, membrane trafficking, and migration. To study the potential importance of phospholipase D in the oncogenic ability of Ras, we used Rat-2 fibroblasts with reduced phospholipase D1 activity (Rat-2V25). Here, we show that H-Ras transformation of Rat-2 fibroblasts requires normal phospholipase D1 activity. WT Rat-2 fibroblasts transfected with the H-RasV12 oncogene grew colonies in soft agar and tumors in nude mice. However, Rat-2V25 cells when transfected with the H-RasV12 oncogene did not form colonies in soft agar or produce tumors when xenografted onto nude mice. Interestingly, in the presence of phosphatidic acid, the product of phospholipase D, growth in soft agar and tumor formation was restored. We also observed a dramatic increase in the expression of phospholipase D1 in colorectal tumors when compared with adjacent normal mucosa. Our studies identify phospholipase D1 as a critical downstream mediator of H-Ras-induced tumor formation.
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Affiliation(s)
- F Gregory Buchanan
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, 691 Preston Building, Nashville, TN 37232, USA.
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Inoki K, Corradetti MN, Guan KL. Dysregulation of the TSC-mTOR pathway in human disease. Nat Genet 2005; 37:19-24. [PMID: 15624019 DOI: 10.1038/ng1494] [Citation(s) in RCA: 745] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 11/23/2004] [Indexed: 12/15/2022]
Abstract
The mammalian target of rapamycin (mTOR) has a central role in the regulation of cell growth. mTOR receives input from multiple signaling pathways, including growth factors and nutrients, to stimulate protein synthesis by phosphorylating key translation regulators such as ribosomal S6 kinase and eukaryote initiation factor 4E binding protein 1. High levels of dysregulated mTOR activity are associated with several hamartoma syndromes, including tuberous sclerosis complex, the PTEN-related hamartoma syndromes and Peutz-Jeghers syndrome. These disorders are all caused by mutations in tumor-suppressor genes that negatively regulate mTOR. Here we discuss the emerging evidence for a functional relationship between the mTOR signaling pathway and several genetic diseases, and we present evidence supporting a model in which dysregulation of mTOR may be a common molecular basis, not only for hamartoma syndromes, but also for other cellular hypertrophic disorders.
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Affiliation(s)
- Ken Inoki
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
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Lisik W, Kahan BD. Inhibitors of mammalian target of rapamycin: mechanism of action explains efficacy and toxicity. Curr Opin Organ Transplant 2004. [DOI: 10.1097/01.mot.0000146725.34815.ea] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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