1
|
Ragupathi A, Kim C, Jacinto E. The mTORC2 signaling network: targets and cross-talks. Biochem J 2024; 481:45-91. [PMID: 38270460 PMCID: PMC10903481 DOI: 10.1042/bcj20220325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/29/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024]
Abstract
The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.
Collapse
Affiliation(s)
- Aparna Ragupathi
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Christian Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| |
Collapse
|
2
|
Ezine E, Lebbe C, Dumaz N. Unmasking the tumourigenic role of SIN1/MAPKAP1 in the mTOR complex 2. Clin Transl Med 2023; 13:e1464. [PMID: 37877351 PMCID: PMC10599286 DOI: 10.1002/ctm2.1464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND Although the PI3K/AKT/mTOR pathway is one of the most altered pathways in human tumours, therapies targeting this pathway have shown numerous adverse effects due to positive feedback paradoxically activating upstream signaling nodes. The somewhat limited clinical efficacy of these inhibitors calls for the development of novel and more effective approaches for targeting the PI3K pathway for therapeutic benefit in cancer. MAIN BODY Recent studies have shown the central role of mTOR complex 2 (mTORC2) as a pro-tumourigenic factor of the PI3K/AKT/mTOR pathway in a number of cancers. SIN1/MAPKAP1 is a major partner of mTORC2, acting as a scaffold and responsible for the substrate specificity of the mTOR catalytic subunit. Its overexpression promotes the proliferation, invasion and metastasis of certain cancers whereas its inhibition decreases tumour growth in vitro and in vivo. It is also involved in epithelial-mesenchymal transition, stress response and lipogenesis. Moreover, the numerous interactions of SIN1 inside or outside mTORC2 connect it with other signaling pathways, which are often disrupted in human tumours such as Hippo, WNT, Notch and MAPK. CONCLUSION Therefore, SIN1's fundamental characteristics and numerous connexions with oncogenic pathways make it a particularly interesting therapeutic target. This review is an opportunity to highlight the tumourigenic role of SIN1 across many solid cancers and demonstrates the importance of targeting SIN1 with a specific therapy.
Collapse
Affiliation(s)
- Emilien Ezine
- INSERMU976Team 1Human Immunology Pathophysiology & Immunotherapy (HIPI)ParisFrance
- Département de DermatologieHôpital Saint LouisAP‐HPParisFrance
| | - Céleste Lebbe
- INSERMU976Team 1Human Immunology Pathophysiology & Immunotherapy (HIPI)ParisFrance
- Département de DermatologieHôpital Saint LouisAP‐HPParisFrance
- Université Paris CitéInstitut de Recherche Saint Louis (IRSL)ParisFrance
| | - Nicolas Dumaz
- INSERMU976Team 1Human Immunology Pathophysiology & Immunotherapy (HIPI)ParisFrance
- Université Paris CitéInstitut de Recherche Saint Louis (IRSL)ParisFrance
| |
Collapse
|
3
|
Pei M, Xu N, Li J, Liu X, Zhang L, Xiao W, Yu Z, Yang P, Peng Y, Zhang J, Hong L, Wu X, Tang W, Lin Z, Zhi F, Li G, Li A, Liu S, Chen Y, Xiang L, Lin J, Wang J. The LINC00501-HSP90B1-STAT3 positive feedback loop promotes malignant behavior in gastric cancer cells. Cell Signal 2023; 108:110711. [PMID: 37156452 DOI: 10.1016/j.cellsig.2023.110711] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/12/2023] [Accepted: 05/06/2023] [Indexed: 05/10/2023]
Abstract
Long non-coding RNAs (lncRNAs) have been implicated in gastric cancer (GC) carcinogenesis and progression. However, the role of LINC00501 in GC growth and metastasis remains unclear. In this study, we found that LINC00501 was frequently upregulated in GC cells and tissues and was closely related to adverse GC clinicopathological features. Aberrant overexpression of LINC00501 promoted GC cell proliferation, invasion, and metastasis both in vitro and in vivo. Mechanistically, LINC00501 stabilized client protein STAT3 from deubiquitylation by directly interacting with cancer chaperone protein HSP90B1. Furthermore, the LINC00501-STAT3 axis modulated GC cell proliferation and metastasis. In turn, STAT3 bound directly to the LINC00501 promoter and positively activated LINC00501 expression, thus forming a positive feedback loop, thereby accelerating tumor growth, invasiveness, and metastasis. In addition, LINC00501 expression was positively correlated with STAT3 and p-STAT3 protein expression levels in gastric clinical samples. Our results reveal that LINC00501 acts as an oncogenic lncRNA and that the LINC00501-HSP90B1-STAT3 positive feedback loop contributes to GC development and progression, suggesting that LINC00501 may be a novel potential biomarker and treatment target for GC.
Collapse
Affiliation(s)
- Miaomiao Pei
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Nanzhu Xu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Jiaying Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xuehua Liu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Gastroenterology, Shunde Hospital, Southern Medical University, Foshan 528300, China
| | - Luyu Zhang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Wushuang Xiao
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhen Yu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Ping Yang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Ying Peng
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Jieming Zhang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Linjie Hong
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xiaosheng Wu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Weimei Tang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhizhao Lin
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Fachao Zhi
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guoxin Li
- Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Aimin Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Side Liu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Gastroenterology, Longgang District People's Hospital, Shenzhen 518172, China
| | - Ye Chen
- Clinical Microecology Center, Shenzhen Hospital, Southern Medical University, Shenzhen 518000, China.
| | - Li Xiang
- Department of Gastroenterology, Longgang District People's Hospital, Shenzhen 518172, China.
| | - Jianjiao Lin
- Department of Gastroenterology, Longgang District People's Hospital, Shenzhen 518172, China.
| | - Jide Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Gastroenterology, Longgang District People's Hospital, Shenzhen 518172, China.
| |
Collapse
|
4
|
Fu J, Li N, He M, Huang D, Zhang P. STAT3 signaling mediates peritoneal fibrosis by activating hyperglycolysis. Am J Transl Res 2022; 14:7552-7565. [PMID: 36398234 PMCID: PMC9641446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Long term peritoneal dialysis leads to peritoneal epithelial-mesenchymal transformation (EMT), angiogenesis, and ultrafiltration failure. Although recent evidence suggests that inhibiting STAT3 (signal transducer and activator of transcription 3) can prevent kidney fibrosis, and that STAT3 can enhance glucose metabolism, the effect of STAT3 in peritoneal fibrosis (PF) has not been clarified. METHODS Our study determined the effects of STAT3 on EMT and key glycolysis enzymes in mesothelial HMrSV5 cells by knockdown and overexpression of STAT3. In addition, we established a rat PF model to examine the role of pharmacologic inhibition of STAT3 or 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 3 (PFKFB3) in this process. RESULTS High glucose (HG) caused the upregulation of α-smooth muscle actin and transforming growth factor beta 1 and the downregulation of E-cadherin, and induced STAT3 activation in HMrSV5 cells. In addition, HMrSV5 cells cultured in high glucose showed high expression of key glycolysis enzymes, which could be inhibited by STAT3 siRNA. Furthermore, treating mesothelial cells with 3PO, the PFKFB3 inhibitor, could attenuate high glucose-induced EMT. Moreover, daily administration of dialysis fluid could induce peritoneal fibrosis. The peritoneal fibrosis was accompanied by enhanced phosphorylation of STAT3 and the upregulation of PFKFB3. The administration of BP-1-102 or 3PO prevented fibrosis and inhibited angiogenesis in PF rats. CONCLUSIONS si-STAT3 attenuated the HG-induced EMT and hyperglycolysis, and the overexpression of STAT3 could induce EMT in HMrSV5 cells. 3PO could markedly attenuate HG-induced EMT by decreasing PFKEB3 in HMrSV5 cells. In addition, we demonstrated that inhibiting STAT3 signaling or peritoneal hyperglycolysis could attenuate peritoneal fibrosis and angiogenesis in vivo. Our findings linked the STAT3/PFKFB3 signaling to the development of PF. HG/STAT3/PFKFB3 might promote the progression of PF through regulating profibrosis and angiogenesis.
Collapse
Affiliation(s)
- Jiao Fu
- Department of Nephrology, The First Affiliated Hospital of Anhui Medical UniversityHefei 230032, Anhui, P.R. China
| | - Nan Li
- Department of Nephrology, The First Affiliated Hospital of Anhui Medical UniversityHefei 230032, Anhui, P.R. China
| | - Mengmeng He
- Department of Nephrology, The First Affiliated Hospital of Anhui Medical UniversityHefei 230032, Anhui, P.R. China
| | - Dake Huang
- Synthetic Laboratory of Basic Medicine College, Anhui Medical UniversityHefei 230032, Anhui, P.R. China
| | - Pei Zhang
- Department of Nephrology, The First Affiliated Hospital of Anhui Medical UniversityHefei 230032, Anhui, P.R. China
| |
Collapse
|
6
|
Yu L, Wei J, Liu P. Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer. Semin Cancer Biol 2021; 85:69-94. [PMID: 34175443 DOI: 10.1016/j.semcancer.2021.06.019] [Citation(s) in RCA: 185] [Impact Index Per Article: 61.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 02/08/2023]
Abstract
Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.
Collapse
Affiliation(s)
- Le Yu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Pengda Liu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| |
Collapse
|