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Molecular Hydrogen Inhibits Colorectal Cancer Growth via the AKT/SCD1 Signaling Pathway. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8024452. [PMID: 35528164 PMCID: PMC9071919 DOI: 10.1155/2022/8024452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/09/2022] [Accepted: 04/12/2022] [Indexed: 12/24/2022]
Abstract
Objective Molecular hydrogen (H2) has been considered a potential therapeutic target in many cancers. Therefore, we sought to assess the potential effect of H2 on colorectal cancer (CRC) in this study. Methods The effect of H2 on the proliferation and apoptosis of RKO, SW480, and HCT116 CRC cell lines was assayed by CCK-8, colony formation, and flow cytometry assays. The effect of H2 on tumor growth was observed in xenograft implantation models (inhalation of 67% hydrogen two hours per day). Western blot and immunohistochemistry analyses were performed to examine the expression of p-PI3K, PI3K, AKT, pAKT, and SCD1 in CRC cell lines and xenograft mouse models. The expression of SCD1 in 491 formalin-fixed, paraffin-embedded CRC specimens was investigated with immunochemistry. The relationship between SCD1 status and clinicopathological characteristics and outcomes was determined. Results Hydrogen treatment suppressed the proliferation of CRC cell lines independent of apoptosis, and the cell lines showed different responses to different doses of H2. Hydrogen also elicited a potent antitumor effect to reduce CRC tumor volume and weight in vivo. Western blot and IHC staining demonstrated that H2 inhibits CRC cell proliferation by decreasing pAKT/SCD1 levels, and the inhibition of cell proliferation induced by H2 was reversed by the AKT activator SC79. IHC showed that SCD1 expression was significantly higher in CRC tissues than in normal epithelial tissues (70.3% vs. 29.7%, p = 0.02) and was correlated with a more advanced TNM stage (III vs. I + II; 75.9% vs. 66.3%, p = 0.02), lymph node metastasis (with vs. without; 75.9% vs. 66.3%, p = 0.02), and patients without a family history of CRC (78.7% vs. 62.1%, p = 0.047). Conclusion This study demonstrates that high concentrations of H2 exert an inhibitory effect on CRC by inhibiting the pAKT/SCD1 pathway. Further studies are warranted for clinical evaluation of H2 as SCD1 inhibitor to target CRC.
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Yun MW, Kim K, Park JY, Chung KY. Conformational Dynamics Analysis of MEK1 Using Hydrogen/Deuterium Exchange Mass Spectrometry. Protein Pept Lett 2021; 28:481-488. [PMID: 33143608 DOI: 10.2174/0929866527666201103152534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/10/2020] [Accepted: 10/10/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Activation of mitogen-activated protein kinases (MAPKs) is regulated by a phosphorylation cascade comprising three kinases, MAPK kinase kinase (MAP3K), MAPK kinase (MAP2K), and MAPK. MAP2K1 and MAPK2K2, also known as MEK1 and MEK2, activate ERK1 and ERK2. The structure of the MAPK signaling cascade has been studied, but high-resolution structural studies of MAP2Ks have often focused on kinase domains or docking sites, but not on full-length proteins. OBJECTIVE To understand the conformational dynamics of MEK1. METHODS Full-length MEK1 was purified from Escherichia coli (BL21), and its conformational dynamics were analyzed using hydrogen/deuterium exchange mass spectrometry (HDX-MS). The effects of ATP binding were examined by co-incubating MEK1 and adenylyl-imidodiphosphate (AMP- PNP), a non-hydrolysable ATP analog. RESULTS MEK1 exhibited mixed EX1/EX2 HDX kinetics within the N-terminal tail through β1, αI, and the C-terminal helix. AMP-PNP binding was found to reduce conformational dynamics within the glycine-rich loop and regions near the DFG motif, along with the activation lip. CONCLUSION We report for the first time that MEK1 has regions that slowly change its folded and unfolded states (mixed EX1/EX2 kinetics) and also report the conformational effects of ATP-binding to MEK1.
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Affiliation(s)
- Min Woo Yun
- School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
| | - Kiae Kim
- School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
| | - Ji Young Park
- School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
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Astl L, Tse A, Verkhivker GM. Interrogating Regulatory Mechanisms in Signaling Proteins by Allosteric Inhibitors and Activators: A Dynamic View Through the Lens of Residue Interaction Networks. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1163:187-223. [DOI: 10.1007/978-981-13-8719-7_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Park JY, Yun Y, Chung KY. Conformations of JNK3α splice variants analyzed by hydrogen/deuterium exchange mass spectrometry. J Struct Biol 2016; 197:271-278. [PMID: 27998708 DOI: 10.1016/j.jsb.2016.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 10/20/2022]
Abstract
c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family that regulate apoptosis, inflammation, cytokine production, and metabolism. MAPKs undergo various splicing within their kinase domains. Unlike other MAPKs, JNKs have alternative splicing at the C-terminus, resulting in long and short variants. Functional or conformational effects due to the elongated C-terminal tail in the long splice variants have not been investigated nor has the conformation of the C-terminal tail been analyzed. Here, we analyzed the conformation of the elongated C-terminal tail and investigated conformational differences between long and short splice variants of JNKs using JNK3α2 and JNK3α1 as models. We adopted hydrogen/deuterium exchange mass spectrometry (HDX-MS) to analyze the conformation. HDX-MS revealed that the C-terminal tail is mostly intrinsically disordered, and that the conformation of the kinase domain of JNK3α2 is more dynamic than that of JNK3α1. The different conformation dynamics between long and short splice variants of JNK3α might affect the cellular functions of JNK3.
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Affiliation(s)
- Ji Young Park
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Youngjoo Yun
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea.
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Gráczer É, Szimler T, Garamszegi A, Konarev PV, Lábas A, Oláh J, Palló A, Svergun DI, Merli A, Závodszky P, Weiss MS, Vas M. Dual Role of the Active Site Residues of Thermus thermophilus 3-Isopropylmalate Dehydrogenase: Chemical Catalysis and Domain Closure. Biochemistry 2016; 55:560-74. [PMID: 26731489 DOI: 10.1021/acs.biochem.5b00839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The key active site residues K185, Y139, D217, D241, D245, and N102 of Thermus thermophilus 3-isopropylmalate dehydrogenase (Tt-IPMDH) have been replaced, one by one, with Ala. A drastic decrease in the kcat value (0.06% compared to that of the wild-type enzyme) has been observed for the K185A and D241A mutants. Similarly, the catalytic interactions (Km values) of these two mutants with the substrate IPM are weakened by more than 1 order of magnitude. The other mutants retained some (1-13%) of the catalytic activity of the wild-type enzyme and do not exhibit appreciable changes in the substrate Km values. The pH dependence of the wild-type enzyme activity (pK = 7.4) is shifted toward higher values for mutants K185A and D241A (pK values of 8.4 and 8.5, respectively). For the other mutants, smaller changes have been observed. Consequently, K185 and D241 may constitute a proton relay system that can assist in the abstraction of a proton from the OH group of IPM during catalysis. Molecular dynamics simulations provide strong support for the neutral character of K185 in the resting state of the enzyme, which implies that K185 abstracts the proton from the substrate and D241 assists the process via electrostatic interactions with K185. Quantum mechanics/molecular mechanics calculations revealed a significant increase in the activation energy of the hydride transfer of the redox step for both D217A and D241A mutants. Crystal structure analysis of the molecular contacts of the investigated residues in the enzyme-substrate complex revealed their additional importance (in particular that of K185, D217, and D241) in stabilizing the domain-closed active conformation. In accordance with this, small-angle X-ray scattering measurements indicated the complete absence of domain closure in the cases of D217A and D241A mutants, while only partial domain closure could be detected for the other mutants. This suggests that the same residues that are important for catalysis are also essential for inducing domain closure.
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Affiliation(s)
- Éva Gráczer
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
| | - Tamás Szimler
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
| | - Anita Garamszegi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
| | - Petr V Konarev
- European Molecular Biology Laboratory , Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany
| | - Anikó Lábas
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics , Gellért tér 4., H-1111 Budapest, Hungary
| | - Julianna Oláh
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics , Gellért tér 4., H-1111 Budapest, Hungary
| | - Anna Palló
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
| | - Dmitri I Svergun
- European Molecular Biology Laboratory , Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany
| | - Angelo Merli
- Dipartimento di Bioscienze, Universitá degli Studi di Parma , Viale G.P. Usberti 23/A, I-43100 Parma, Italy
| | - Péter Závodszky
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
| | - Manfred S Weiss
- Macromolecular Crystallography (HZB-MX), Helmholtz-Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Mária Vas
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar tudósok krt. 2., H-1117 Budapest, Hungary
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