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Madhukar G, Subbarao N. Potential inhibitors of RPS6KB2 and NRF2 in head and neck squamous cell carcinoma. J Biomol Struct Dyn 2024; 42:1875-1900. [PMID: 37160694 DOI: 10.1080/07391102.2023.2205946] [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: 10/03/2022] [Accepted: 04/08/2023] [Indexed: 05/11/2023]
Abstract
Among the major altered pathways in head and neck squamous cell carcinoma, AKT/mTORC1/S6K and NRF2/KEAP1 pathway are quite significant. The overexpression and overstimulation of proteins from both these pathways makes them the promising candidates in cancer therapeutics. Inhibiting mTOR has been in research from past several decades but the tumour heterogeneity, and upregulation of several compensatory feed-back mechanisms, encourages to explore other downstream targets for inhibiting the pathway. One such downstream effectors of mTOR is S6K2. It is reported to be overexpressed in cancers such as head and neck cancer, breast cancer and prostate cancer. In case of NRF2/KEAP1 pathway, nuclear factor erythroid 2-related factor 2 (NFE2L2 or NRF2) is overexpressed in ∼90% of head and neck squamous cell carcinoma (HNSCC) cases. It associates with poor survival rate and therapeutic resistance in HNSCC treatment. NRF2 pathway is the primary antioxidant pathway in the cell which also serves pro-tumorigenic functions, such as repression of apoptosis, cell proliferation support and chemoresistance. The aim of this work was to explore S6K2 and NRF2 and identify novel and potential inhibitors against them for treating head and neck squamous cell carcinoma. Since the crystal structure of S6K2 was not available at the time of this study, we modelled its structure using homology modelling and performed high throughput screening, molecular dynamics simulations, free energy calculations and protein-ligand interaction studies to identify the inhibitors. We identified natural compounds Crocin and Gypenoside XVII against S6K2 and Chebulinic acid and Sennoside A against NRF2. This study provides a significant in-depth understanding of the two studied pathways and therefore can be used in the development of potential therapeutics against HNSCC.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Geet Madhukar
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
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Ma Q, Yang Y, Chen S, Cheng H, Gong P, Hao J. Ribosomal protein S6 kinase 2 (RPS6KB2) is a potential immunotherapeutic target for cancer that upregulates proinflammatory cytokines. Mol Biol Rep 2024; 51:229. [PMID: 38281249 DOI: 10.1007/s11033-023-09134-5] [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: 08/19/2023] [Accepted: 12/08/2023] [Indexed: 01/30/2024]
Abstract
BACKGROUND Cancer is still a leading cause of mortality. Over the years, cancer therapy has undergone significant advances driven by advancements in science and technology. A promising area of drug discovery in this field involves the development of therapeutic targets for cancer treatment. The urgent need to identify new pharmacological targets arises from the impact of tumor resistance on the effectiveness of current medications. Specifically, the RPS6KB2 gene on chromosome 11 has been implicated in cell cycle regulation and exhibits higher expression levels in tumor tissue. Given this association, there is a potential for this gene to serve as a target for cancer treatment. METHODS We conducted an analysis using the GTEx, TCGA, and CCLE databases to explore the relationship between RPS6KB2 and immune infiltration, the tumor microenvironment (TME), microsatellite instability (MSI), and more. Cell proliferation was assessed using EDU detection, while cell invasion and migration were evaluated via wound healing and Transwell assays. Additionally, western blot analysis was employed to measure expression of Bax, Bcl-2, MMP2, MMP9, PCNA, and proinflammatory factors. RESULTS Through data analysis and molecular biology methods, our study carefully examined the potential role of RPS6KB2 in cancer therapy. The data revealed that RPS6KB2 is aberrantly expressed in most cancers and is associated with poor prognosis. Further analysis indicated its involvement in cancer cell apoptosis and migration, as well as its role in cancer immune processes. We validated the significance of RPS6KB2 in hepatocellular carcinoma (HCC), highlighting its capacity to upregulate proinflammatory cytokines. CONCLUSION Our research indicates that RPS6KB2 is a prognostic biomarker associated with immune infiltration in cancer that can affect antitumor immunity by increasing secretion of proinflammatory factors, providing a potential drug target for cancer treatment.
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Affiliation(s)
- Qiang Ma
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Department of Oncology, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yipin Yang
- The First Clinical Medical College of Anhui Medical University, Hefei, China
| | - Shuwen Chen
- The First Clinical Medical College of Anhui Medical University, Hefei, China
| | - Hao Cheng
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Peng Gong
- Department of Pharmacy, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
| | - Jiqing Hao
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
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Gerstenecker S, Haarer L, Schröder M, Kudolo M, Schwalm MP, Wydra V, Serafim RAM, Chaikuad A, Knapp S, Laufer S, Gehringer M. Discovery of a Potent and Highly Isoform-Selective Inhibitor of the Neglected Ribosomal Protein S6 Kinase Beta 2 (S6K2). Cancers (Basel) 2021; 13:cancers13205133. [PMID: 34680283 PMCID: PMC8534050 DOI: 10.3390/cancers13205133] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/04/2021] [Accepted: 10/08/2021] [Indexed: 12/27/2022] Open
Abstract
Simple Summary The two human p70 ribosomal S6 kinases, S6K1 and S6K2, have been associated with a variety of cellular processes and human pathologies, especially cancer. Thus far, only S6K1 was thoroughly studied and selectively addressed by small molecule inhibitors. Despite growing evidence suggesting S6K2 as a promising anticancer target, this isoform has been severely neglected, which can partly be attributed to the lack of isoform-selective inhibitors to study its function. By exploiting a cysteine residue exclusive to S6K2, we were able to generate the first known isoform-selective S6K2 inhibitor. Besides its excellent selectivity against S6K1 and other human kinases, the compound showed weak intrinsic reactivity and promising in vitro metabolic stability. Our proof-of-concept study provides a basis for the development of high quality S6K2 chemical probes to validate this kinase as a target for therapeutic interventions. Abstract The ribosomal protein S6 kinase beta 2 (S6K2) is thought to play an important role in malignant cell proliferation, but is understudied compared to its closely related homolog S6 kinase beta 1 (S6K1). To better understand the biological function of S6K2, chemical probes are needed, but the high similarity between S6K2 and S6K1 makes it challenging to selectively address S6K2 with small molecules. We were able to design the first potent and highly isoform-specific S6K2 inhibitor from a known S6K1-selective inhibitor, which was merged with a covalent inhibitor engaging a cysteine located in the hinge region in the fibroblast growth factor receptor kinase (FGFR) 4 via a nucleophilic aromatic substitution (SNAr) reaction. The title compound shows a high selectivity over kinases with an equivalently positioned cysteine, as well as in a larger kinase panel. A good stability towards glutathione and Nα-acetyl lysine indicates a non-promiscuous reactivity pattern. Thus, the title compound represents an important step towards a high-quality chemical probe to study S6K2-specific signaling.
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Affiliation(s)
- Stefan Gerstenecker
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
| | - Lisa Haarer
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
| | - Martin Schröder
- Department of Biochemistry, Chemistry and Pharmacy, Institute for Pharmaceutical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany; (M.S.); (M.P.S.); (A.C.); (S.K.)
- Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Mark Kudolo
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
| | - Martin P. Schwalm
- Department of Biochemistry, Chemistry and Pharmacy, Institute for Pharmaceutical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany; (M.S.); (M.P.S.); (A.C.); (S.K.)
- Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Valentin Wydra
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
| | - Ricardo A. M. Serafim
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
| | - Apirat Chaikuad
- Department of Biochemistry, Chemistry and Pharmacy, Institute for Pharmaceutical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany; (M.S.); (M.P.S.); (A.C.); (S.K.)
- Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Stefan Knapp
- Department of Biochemistry, Chemistry and Pharmacy, Institute for Pharmaceutical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany; (M.S.); (M.P.S.); (A.C.); (S.K.)
- Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
- German Translational Cancer Network (DKTK) Site Frankfurt/Mainz, Frankfurt Cancer Institute (FCI), 60596 Frankfurt, Germany
| | - Stefan Laufer
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
- Cluster of Excellence iFIT (EXC 2180) ‘Image-Guided & Functionally Instructed Tumor Therapies’, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
- Tübingen Center for Academic Drug Discovery, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
| | - Matthias Gehringer
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; (S.G.); (L.H.); (M.K.); (V.W.); (R.A.M.S.); (S.L.)
- Cluster of Excellence iFIT (EXC 2180) ‘Image-Guided & Functionally Instructed Tumor Therapies’, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
- Correspondence: ; Tel.: +49-7071-29-74582
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Distinct Roles of mTOR Targets S6K1 and S6K2 in Breast Cancer. Int J Mol Sci 2020; 21:ijms21041199. [PMID: 32054043 PMCID: PMC7072743 DOI: 10.3390/ijms21041199] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a master regulator of protein translation, metabolism, cell growth and proliferation. It forms two complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2). mTORC1 is frequently deregulated in many cancers, including breast cancer, and is an important target for cancer therapy. The immunosuppressant drug rapamycin and its analogs that inhibit mTOR are currently being evaluated for their potential as anti-cancer agents, albeit with limited efficacy. mTORC1 mediates its function via its downstream targets 40S ribosomal S6 kinases (S6K) and eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). There are two homologs of S6K: S6K1 and S6K2. Most of the earlier studies focused on S6K1 rather than S6K2. Because of their high degree of structural homology, it was generally believed that they behave similarly. Recent studies suggest that while they may share some functions, they may also exhibit distinct or even opposite functions. Both homologs have been implicated in breast cancer, although how they contribute to breast cancer may differ. The purpose of this review article is to compare and contrast the expression, structure, regulation and function of these two S6K homologs in breast cancer.
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